Firepower威脅防禦IGMP和組播基礎知識故障排除

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已更新: 2022 年 5 月 19 日

文件 ID:217891

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簡介

本檔案介紹多點傳送的基礎知識和Firepower威脅防禦(FTD)如何實施網際網路群組管理通訊協定(IGMP)。

必要條件

需求

基本IP路由知識。

採用元件

本文中的資訊是根據特定實驗室環境內的裝置所建立。文中使用到的所有裝置皆從已清除（預設）的組態來啟動。如果您的網路運作中，請確保您瞭解任何指令可能造成的影響。

本文內容也適用於自適應安全裝置(ASA)軟體。

本文中的資訊係根據以下軟體和硬體版本：

Cisco Firepower 4125威脅防禦版本7.1.0。
Firepower管理中心(FMC)版本7.1.0。
ASA版本9.19.1。

背景資訊

定義

單播=從一台主機到另一台主機（一對一）。
廣播=從一台主機到所有可能的主機（一對全）。
組播=從一組主機的主機到一組主機（一對多或多對多）。
任播=從主機到組的最近主機（一對多對一）。

基礎知識

組播RFC 988由Steve Deering於1986年編寫。
IPv4多點傳送使用範圍224.0.0.0/4（前4位1110） — 224.0.0.0 - 239.255.255.255。
對於IPv4，第2層MAC地址來自第3層組播IP: 01005e（24位）+ 25^位(always 0 + 23位組播IPv4地址的更低位)。
IPv6多點傳送使用FF00::/8範圍，比IPv4多點傳送更靈活，因為它可以嵌入集結點(RP)IP。
對於IPv6，第2層MAC地址來自第3層組播：3333 + 32位組播IPv6地址的更低位。
組播的優勢：由於源上的負載減少，效率提高。效能，因為它避免了流量重複或泛洪。
組播的缺點：傳輸不可靠（基於UDP）、無擁塞規避、傳送順序不當。
公共Internet不支援組播，因為它需要路徑中的所有裝置來啟用組播。通常在所有裝置都處於公共管理許可權下時使用。
典型組播應用：內部影片流、視訊會議。

多點傳送與複製的單點傳送

在複製單播中，源建立同一單播資料包（複製副本）的多個副本，並將它們傳送到多個目標主機。組播將負擔從源主機轉移到網路，而在複製單播中，所有工作都在源主機上完成。

設定

IGMP基礎知識

IGMP是組播接收器和本地L3裝置（通常為路由器）之間的「語言」。
IGMP是第3層通訊協定（類似ICMP），並使用IP通訊協定編號2。
目前有3個IGMP版本。防火牆上的預設IGMP版本是版本2。目前僅支援版本1和2。
IGMPv1和IGMPv2之間的主要差異如下：

IGMPv1沒有離開組消息。
IGMPv1沒有特定於組的查詢（當主機離開組播組時防火牆使用）。
IGMPv1沒有查詢器選擇過程。

ASA/FTD目前不支援IGMPv3，但作為參考，IGMPv2和IGMPv3之間的重要區別在於在IGMPv3中包含一個源和組特定查詢，該查詢用於源特定多點傳送(SSM)。
IGMPv1/IGMPv2/IGMPv3查詢= 224.0.0.1
IGMPv2離開= 224.0.0.2
IGMPv3成員報告= 224.0.0.22
如果主機要加入，可以傳送未經請求的IGMP成員報告消息：

igmp_membership

從防火牆的角度來看，IGMP查詢有兩種型別：常規查詢和組特定查詢
當防火牆收到IGMP離開組消息時，它必須檢查該組在子網中是否有其他成員。因此，防火牆會傳送一個群組特定查詢：

igmp_membership_specific

在有多個路由器/防火牆的子網上，選擇querier（傳送所有IGMP查詢的裝置）：

firepower# show igmp interface INSIDE
INSIDE is up, line protocol is up
  Internet address is 192.168.1.97/24
  IGMP is enabled on interface
  Current IGMP version is 2
  IGMP query interval is 125 seconds
  IGMP querier timeout is 60 seconds
  IGMP max query response time is 10 seconds
  Last member query response interval is 1 seconds
  Inbound IGMP access group is:
  IGMP limit is 500, currently active joins: 2
  Cumulative IGMP activity: 21 joins, 20 leaves
  IGMP querying router is 192.168.1.97 (this system)  <-- IGMP querier

在FTD上（類似於傳統ASA），您可以啟用debug igmp以檢視與IGMP相關的消息：

firepower# debug igmp
IGMP debugging is on
IGMP: Received v2 Query on DMZ from 192.168.6.1
IGMP: Received v2 Report on INSIDE from 192.168.1.50 for 239.255.255.250   <-- Received an IGMP packet
IGMP: group_db: add new group 239.255.255.250 on INSIDE
IGMP: MRIB updated (*,239.255.255.250) : Success
IGMP: Switching to EXCLUDE mode for 239.255.255.250 on INSIDE
IGMP: Updating EXCLUDE group timer for 239.255.255.250
IGMP: Received v2 Report on INSIDE from 192.168.1.50 for 230.10.10.10
IGMP: group_db: add new group 230.10.10.10 on INSIDE
IGMP: MRIB updated (*,230.10.10.10) : Success
IGMP: Switching to EXCLUDE mode for 230.10.10.10 on INSIDE
IGMP: Updating EXCLUDE group timer for 230.10.10.10
IGMP: Send v2 general Query on INSIDE
IGMP: Received v2 Query on INSIDE from 192.168.1.97
IGMP: Send v2 general Query on OUTSIDE
IGMP: Received v2 Query on OUTSIDE from 192.168.103.91
IGMP: Received v2 Report on INSIDE from 192.168.1.50 for 239.255.255.250
IGMP: Updating EXCLUDE group timer for 239.255.255.250
IGMP: Received v2 Report on INSIDE from 192.168.1.50 for 230.10.10.10
IGMP: Updating EXCLUDE group timer for 230.10.10.10

主機通常使用離開組消息(IGMPv2)離開組播組。

igmp_leave

任務1 — 控制平面組播流量

OSPF_topology

在FTD和ASA之間配置OSPFv2和OSPFv3。檢查2台裝置如何處理OSPF生成的L2和L3組播流量。

解決方案

OSPFv2配置

ospf_config_ftd

ospf_config_interface

類似地，對於OSPFv3

FTD CLI上的組態：

router ospf 1
 network 192.168.103.0 255.255.255.0 area 0
 log-adj-changes
!
ipv6 router ospf 1
 no graceful-restart helper
 log-adjacency-changes
!
interface Ethernet1/4
nameif OUTSIDE
security-level 0
ip address 192.168.103.91 255.255.255.0
ipv6 address fc00:103::91/64
ospf authentication null
ipv6 ospf 1 area 0

此組態在FTD加速安全路徑(ASP)允許表中建立這些專案，以便入口多點傳播流量不會受到封鎖：

firepower# show asp table classify domain permit
...
in id=0x14f922db85f0, priority=13, domain=permit, deny=false         <-- permit the packets
        hits=1, user_data=0x0, cs_id=0x0, reverse, flags=0x0, protocol=89
        src ip/id=0.0.0.0, mask=0.0.0.0, port=0, tag=any
        dst ip/id=224.0.0.5, mask=255.255.255.255, port=0, tag=any, dscp=0x0, nsg_id=none     <-- OSPF for IPv4
        input_ifc=OUTSIDE(vrfid:0), output_ifc=identity(vrfid:0)     <-- ingress interface
in id=0x14f922db9350, priority=13, domain=permit, deny=false         <-- permit the packets
        hits=0, user_data=0x0, cs_id=0x0, reverse, flags=0x0, protocol=89
        src ip/id=0.0.0.0, mask=0.0.0.0, port=0, tag=any
        dst ip/id=224.0.0.6, mask=255.255.255.255, port=0, tag=any, dscp=0x0, nsg_id=none     <-- OSPF for IPv4
        input_ifc=OUTSIDE(vrfid:0), output_ifc=identity(vrfid:0)     <-- ingress interface

對於IPv6:

...
in id=0x14f923fb16f0, priority=13, domain=permit, deny=false      <-- permit the packets
        hits=1, user_data=0x0, cs_id=0x0, reverse, flags=0x0, protocol=89
        src ip/id=::/0, port=0, tag=any
        dst ip/id=ff02::5/128, port=0, tag=any, , nsg_id=none     <-- OSPF for IPv6
        input_ifc=OUTSIDE(vrfid:0), output_ifc=identity(vrfid:0)  <-- ingress interface
in id=0x14f66e9d4780, priority=13, domain=permit, deny=false      <-- permit the packets
        hits=0, user_data=0x0, cs_id=0x0, reverse, flags=0x0, protocol=89
        src ip/id=::/0, port=0, tag=any
        dst ip/id=ff02::6/128, port=0, tag=any, , nsg_id=none     <-- OSPF for IPv6
        input_ifc=OUTSIDE(vrfid:0), output_ifc=identity(vrfid:0)  <-- ingress interface
...

OSPFv2和OSPFv3鄰接關係已啟動：

firepower# show ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
192.168.103.50 1 FULL/BDR 0:00:35 192.168.103.50 OUTSIDE   <-- OSPF neighbor is up

firepower# show ipv6 ospf neighbor
Neighbor ID Pri State Dead Time Interface ID Interface
192.168.103.50 1 FULL/BDR 0:00:34 3267035482 OUTSIDE       <-- OSPF neighbor is up

以下是終止到該盒的組播OSPF會話：

firepower# show conn all | include OSPF
OSPF OUTSIDE fe80::2be:75ff:fef6:1d8e NP Identity Ifc ff02::5, idle 0:00:09, bytes 5924, flags
OSPF OUTSIDE 192.168.103.50 NP Identity Ifc 224.0.0.5, idle 0:00:03, bytes 8904, flags
OSPF OUTSIDE ff02::5 NP Identity Ifc fe80::f6db:e6ff:fe33:442e, idle 0:00:01, bytes 6304, flags
OSPF OUTSIDE 224.0.0.5 NP Identity Ifc 192.168.103.91, idle 0:00:00, bytes 25220, flags

作為測試，啟用IPv4捕獲並清除與裝置的連線：

firepower# capture CAP interface OUTSIDE trace
firepower# clear conn all
12 connection(s) deleted.
firepower# clear capture CAP
firepower# !

警告：這將導致中斷！展示的範例僅作演示之用！

捕獲的OSPF資料包：

firepower# show capture CAP | include proto-89
1: 12:25:33.142189 192.168.103.50 > 224.0.0.5 ip-proto-89, length 60
2: 12:25:33.702691 192.168.103.91 > 224.0.0.5 ip-proto-89, length 60
7: 12:25:36.317000 192.168.206.100 > 224.0.0.5 ip-proto-89, length 56
8: 12:25:36.952587 fe80::2be:75ff:fef6:1d8e > ff02::5 ip-proto-89 40 [flowlabel 0xe] [hlim 1]
12: 12:25:41.282608 fe80::f6db:e6ff:fe33:442e > ff02::5 ip-proto-89 40 [flowlabel 0xe] [hlim 1]

以下是防火牆處理OSPFv2多點傳送封包的方式：

firepower# show capture CAP packet-number 1 trace
115 packets captured

1: 12:25:33.142189 192.168.103.50 > 224.0.0.5 ip-proto-89, length 60    <-- The first packet of the flow
Phase: 1
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 6344 ns
Config:
Additional Information:
MAC Access list

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 6344 ns
Config:
Implicit Rule
Additional Information:
MAC Access list

Phase: 3
Type: ROUTE-LOOKUP
Subtype: No ECMP load balancing
Result: ALLOW
Elapsed time: 10736 ns
Config:
Additional Information:
Destination is locally connected. No ECMP load balancing.
Found next-hop 192.168.103.50 using egress ifc OUTSIDE(vrfid:0)

Phase: 4
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 5205 ns
Config:
Implicit Rule
Additional Information:

Phase: 5
Type: NAT
Subtype: per-session
Result: ALLOW
Elapsed time: 5205 ns
Config:
Additional Information:

Phase: 6
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Elapsed time: 5205 ns
Config:
Additional Information:

Phase: 7
Type: CLUSTER-REDIRECT
Subtype: cluster-redirect
Result: ALLOW
Elapsed time: 29280 ns
Config:
Additional Information:

Phase: 8
Type: MULTICAST
Subtype:
Result: ALLOW
Elapsed time: 976 ns
Config:
Additional Information:

Phase: 9                     
Type: OSPF                   <-- The OSPF process
Subtype: ospf
Result: ALLOW
Elapsed time: 488 ns
Config:
Additional Information:

Phase: 10
Type: FLOW-CREATION
Subtype:
Result: ALLOW
Elapsed time: 13176 ns
Config:
Additional Information:
New flow created with id 620, packet dispatched to next module

Result:
input-interface: OUTSIDE(vrfid:0)
input-status: up
input-line-status: up
output-interface: OUTSIDE(vrfid:0)
output-status: up
output-line-status: up
Action: allow
Time Taken: 82959 ns

以下是防火牆處理OSPFv3多點傳送封包的方式：

firepower# show capture CAP packet-number 8 trace
274 packets captured

8: 12:25:36.952587 fe80::2be:75ff:fef6:1d8e > ff02::5 ip-proto-89 40 [flowlabel 0xe] [hlim 1]  <-- The first packet of the flow
Phase: 1
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 7564 ns
Config:
Additional Information:
MAC Access list

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 7564 ns
Config:
Implicit Rule
Additional Information:
MAC Access list

Phase: 3
Type: ROUTE-LOOKUP
Subtype: No ECMP load balancing
Result: ALLOW
Elapsed time: 8296 ns
Config:
Additional Information:
Destination is locally connected. No ECMP load balancing.
Found next-hop ff02::5 using egress ifc identity(vrfid:0)

Phase: 4
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 8784 ns
Config:
Implicit Rule
Additional Information:

Phase: 5
Type: NAT
Subtype: per-session
Result: ALLOW
Elapsed time: 8784 ns
Config:
Additional Information:

Phase: 6
Type: CLUSTER-REDIRECT
Subtype: cluster-redirect
Result: ALLOW
Elapsed time: 27816 ns
Config:
Additional Information:

Phase: 7
Type: OSPF                    <-- The OSPF process
Subtype: ospf
Result: ALLOW
Elapsed time: 976 ns
Config:
Additional Information:

Phase: 8
Type: FLOW-CREATION
Subtype:
Result: ALLOW
Elapsed time: 13664 ns
Config:
Additional Information:
New flow created with id 624, packet dispatched to next module

Result:
input-interface: OUTSIDE(vrfid:0)
input-status: up
input-line-status: up
output-interface: NP Identity Ifc
Action: allow
Time Taken: 83448 ns

任務2 — 配置基本組播

拓撲

需求

配置防火牆，以便將來自伺服器的組播流量流傳輸到IP 230.10.10.10上的組播客戶端

解決方案

從防火牆的角度來看，最低配置是啟用全域性組播路由。這將在所有防火牆介面上啟用後台的IGMP和PIM。

在FMC UI上：

enable_ftd_multicast

在防火牆CLI上，這是推送的配置：

firepower# show run multicast-routing
multicast-routing                   <-- Multicast routing is enabled

IGMP驗證

firepower# show igmp interface
diagnostic is up, line protocol is up
  Internet address is 0.0.0.0/0
  IGMP is disabled on interface
INSIDE is up, line protocol is up          <-- The interface is UP
  Internet address is 192.168.1.24/24
  IGMP is enabled on interface             <-- IGMP is enabled on the interface
  Current IGMP version is 2                <-- IGMP version
  IGMP query interval is 125 seconds
  IGMP querier timeout is 255 seconds
  IGMP max query response time is 10 seconds
  Last member query response interval is 1 seconds
  Inbound IGMP access group is:
  IGMP limit is 500, currently active joins: 1
  Cumulative IGMP activity: 4 joins, 3 leaves
  IGMP querying router is 192.168.1.24 (this system)
OUTSIDE is up, line protocol is up         <-- The interface is UP
  Internet address is 192.168.103.91/24
  IGMP is enabled on interface             <-- IGMP is enabled on the interface
  Current IGMP version is 2                <-- IGMP version
  IGMP query interval is 125 seconds
  IGMP querier timeout is 255 seconds
  IGMP max query response time is 10 seconds
  Last member query response interval is 1 seconds
  Inbound IGMP access group is:
  IGMP limit is 500, currently active joins: 1
  Cumulative IGMP activity: 1 joins, 0 leaves
  IGMP querying router is 192.168.103.91 (this system)

firepower# show igmp group
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
239.255.255.250 INSIDE 00:09:05 00:03:19 192.168.1.50
239.255.255.250 OUTSIDE 00:06:01 00:02:33 192.168.103.60

firepower# show igmp traffic
IGMP Traffic Counters
Elapsed time since counters cleared: 03:40:48 Received Sent

                              Received     Sent
Valid IGMP Packets            21           207
Queries                       0            207
Reports                       15           0       <-- IGMP Reports received and sent
Leaves                        6            0
Mtrace packets                0            0
DVMRP packets                 0            0
PIM packets                   0            0

Errors:
Malformed Packets             0
Martian source                0
Bad Checksums                 0

PIM驗證

firepower# show pim interface

Address          Interface          PIM  Nbr   Hello  DR         DR
                                       Count Intvl  Prior

0.0.0.0          diagnostic         off  0     30     1          not elected
192.168.1.24     INSIDE             on   0     30     1          this system
192.168.103.91   OUTSIDE            on   0     30     1          this system

MFIB驗證

firepower# show mfib
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
             AR - Activity Required, K - Keepalive
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
Other counts: Total/RPF failed/Other drops
Interface Flags: A - Accept, F - Forward, NS - Negate Signalling
             IC - Internal Copy, NP - Not platform switched
             SP - Signal Present
Interface Counts: FS Pkt Count/PS Pkt Count

(*,224.0.1.39) Flags: S K
   Forwarding: 0/0/0/0, Other: 0/0/0   <-- The Forwarding counters are: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
(*,224.0.1.40) Flags: S K
   Forwarding: 0/0/0/0, Other: 8/8/0   <-- The Other counters are: Total/RPF failed/Other drops
(*,232.0.0.0/8) Flags: K
   Forwarding: 0/0/0/0, Other: 0/0/0

通過防火牆的組播流量

在此案例中，VLC媒體播放器應用程式用作多點傳送伺服器和使用者端，以測試多點傳送流量：

multicast_through_ftd

VLC多點傳送伺服器組態：

vlc_stream

vlc_add_file

在下一個螢幕上，選擇Next。

選擇格式：

vlc_add_method

指定組播IP和埠：

vlc_add_ip

vlc_enable

在FTD防火牆上啟用LINA擷取：

firepower# capture INSIDE interface INSIDE match ip host 192.168.103.60 host 230.10.10.10
firepower# capture OUTSIDE interface OUTSIDE trace match ip host 192.168.103.60 host 230.10.10.10

為裝置選擇Stream按鈕以啟動組播流：

vlc_start_stream

啟用「loop」選項，以便連續傳送流：

vlc_loop

驗證（非操作方案）

此方案演示了一個非操作方案。目標是演示防火牆行為。

防火牆裝置會收到組播流，但不會轉發它：

firepower# show capture
capture INSIDE type raw-data interface INSIDE [Capturing - 0 bytes]     <-- No packets sent or received
match ip host 192.168.103.60 host 230.10.10.10
capture OUTSIDE type raw-data trace interface OUTSIDE [Buffer Full - 524030 bytes]  <-- The buffer is full
match ip host 192.168.103.60 host 230.10.10.10

防火牆LINA ASP丟棄顯示：

firepower# clear asp drop
firepower# show asp drop

Frame drop:
  Punt rate limit exceeded (punt-rate-limit)                         232  <-- The multicast packets were dropped
  Flow is denied by configured rule (acl-drop)                         2
  FP L2 rule drop (l2_acl)                                             2

Last clearing: 18:38:42 UTC Oct 12 2018 by enable_15

Flow drop:

Last clearing: 08:45:41 UTC May 17 2022 by enable_15

要跟蹤資料包，需要捕獲組播流的第一個資料包。因此，請清除當前流量：

firepower# clear capture OUTSIDE
firepower# clear conn all addr 230.10.10.10
2 connection(s) deleted.

firepower# show capture OUTSIDE

379 packets captured

1: 08:49:04.537875 192.168.103.60.54100 > 230.10.10.10.5005: udp 64
2: 08:49:04.537936 192.168.103.60.54099 > 230.10.10.10.5004: udp 1328
3: 08:49:04.538027 192.168.103.60.54099 > 230.10.10.10.5004: udp 1328
4: 08:49:04.538058 192.168.103.60.54099 > 230.10.10.10.5004: udp 1328
5: 08:49:04.538058 192.168.103.60.54099 > 230.10.10.10.5004: udp 1328
6: 08:49:04.538073 192.168.103.60.54099 > 230.10.10.10.5004: udp 1328
...

「detail」選項顯示組播MAC地址：

firepower# show capture OUTSIDE detail

379 packets captured

1: 08:49:04.537875 0050.569d.344a 0100.5e0a.0a0a 0x0800 Length: 106
192.168.103.60.54100 > 230.10.10.10.5005: [udp sum ok] udp 64 (ttl 100, id 19759)
2: 08:49:04.537936 0050.569d.344a 0100.5e0a.0a0a 0x0800 Length: 1370
192.168.103.60.54099 > 230.10.10.10.5004: [udp sum ok] udp 1328 (ttl 100, id 19760)
3: 08:49:04.538027 0050.569d.344a 0100.5e0a.0a0a 0x0800 Length: 1370
192.168.103.60.54099 > 230.10.10.10.5004: [udp sum ok] udp 1328 (ttl 100, id 19761)
...

實際封包的追蹤軌跡顯示封包允許通過，但實際發生的情況並非如此：

firepower# show capture OUTSIDE packet-number 1 trace
379 packets captured

1: 08:49:04.537875 192.168.103.60.54100 > 230.10.10.10.5005: udp 64
Phase: 1
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 11712 ns
Config:
Additional Information:
MAC Access list

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 11712 ns
Config:
Implicit Rule
Additional Information:
MAC Access list

Phase: 3
Type: ROUTE-LOOKUP
Subtype: No ECMP load balancing
Result: ALLOW
Elapsed time: 7808 ns
Config:
Additional Information:
Destination is locally connected. No ECMP load balancing.
Found next-hop 192.168.103.60 using egress ifc OUTSIDE(vrfid:0)

Phase: 4
Type: ACCESS-LIST
Subtype: log
Result: ALLOW
Elapsed time: 5246 ns
Config:
access-group CSM_FW_ACL_ global
access-list CSM_FW_ACL_ advanced permit ip any any rule-id 268434432
access-list CSM_FW_ACL_ remark rule-id 268434432: ACCESS POLICY: mzafeiro_empty - Default
access-list CSM_FW_ACL_ remark rule-id 268434432: L4 RULE: DEFAULT ACTION RULE
Additional Information:
This packet will be sent to snort for additional processing where a verdict will be reached

Phase: 5
Type: CONN-SETTINGS
Subtype:
Result: ALLOW
Elapsed time: 5246 ns
Config:
class-map class-default
match any
policy-map global_policy
class class-default
set connection advanced-options UM_STATIC_TCP_MAP
service-policy global_policy global
Additional Information:

Phase: 6
Type: NAT
Subtype: per-session
Result: ALLOW
Elapsed time: 5246 ns
Config:
Additional Information:

Phase: 7
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Elapsed time: 5246 ns
Config:
Additional Information:

Phase: 8
Type: CLUSTER-REDIRECT
Subtype: cluster-redirect
Result: ALLOW
Elapsed time: 31232 ns
Config:
Additional Information:

Phase: 9
Type: MULTICAST       <-- multicast process
Subtype:
Result: ALLOW
Elapsed time: 976 ns
Config:
Additional Information:

Phase: 10
Type: FLOW-CREATION   <-- the packet belongs to a new flow
Subtype:
Result: ALLOW          
Elapsed time: 20496 ns
Config:
Additional Information:
New flow created with id 3705, packet dispatched to next module

Result:
input-interface: OUTSIDE(vrfid:0)   
input-status: up
input-line-status: up
output-interface: OUTSIDE(vrfid:0)
output-status: up
output-line-status: up
Action: allow            <-- The packet is allowed
Time Taken: 104920 ns

根據mroute和mfib計數器，由於傳出介面清單(OIL)為空，因此丟棄了資料包：

firepower# show mroute

Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group,
C - Connected, L - Local, I - Received Source Specific Host Report,
P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,
J - Join SPT
Timers: Uptime/Expires
Interface state: Interface, State

(192.168.103.60, 230.10.10.10), 00:01:33/00:01:56, flags: SPF
Incoming interface: OUTSIDE          
RPF nbr: 192.168.103.60
Outgoing interface list: Null        <-- The OIL is empty!

(*, 239.255.255.250), 00:01:50/never, RP 0.0.0.0, flags: SCJ
Incoming interface: Null
RPF nbr: 0.0.0.0
Immediate Outgoing interface list:
INSIDE, Forward, 00:01:50/never

MFIB計數器顯示RPF失敗，在這種情況下，並非實際發生的情況：

firepower# show mfib 230.10.10.10
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
             AR - Activity Required, K - Keepalive
firepower# show mfib 230.10.10.10
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
AR - Activity Required, K - Keepalive
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second   <-- Multicast forwarding counters
Other counts: Total/RPF failed/Other drops            <-- Multicast drop counters
Interface Flags: A - Accept, F - Forward, NS - Negate Signalling
             IC - Internal Copy, NP - Not platform switched
             SP - Signal Present
Interface Counts: FS Pkt Count/PS Pkt Count

(192.168.103.60,230.10.10.10) Flags: K
   Forwarding: 0/0/0/0, Other: 650/650/0       <-- Allowed and dropped multicast packets

「show mfib count」輸出中的類似RPF失敗：

firepower# show mfib count
IP Multicast Statistics
8 routes, 4 groups, 0.25 average sources per group
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kilobits per second
Other counts: Total/RPF failed/Other drops(OIF-null, rate-limit etc)
Group: 224.0.1.39
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 224.0.1.40
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 230.10.10.10
  Source: 192.168.103.60,
    Forwarding: 0/0/0/0, Other: 1115/1115/0   <-- Allowed and dropped multicast packets
  Tot. shown: Source count: 1, pkt count: 0
Group: 232.0.0.0/8
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 239.255.255.250
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0

設定VLC多點傳送接收器：

vlc_play_stream

指定組播源IP並選擇播放：

在後端中，只要選擇播放，主機就會宣佈願意加入特定組播組並傳送IGMP報告消息：

multicast_through_ftd_ok

如果啟用調試，可以看到IGMP報告消息：

firepower# debug igmp group 230.10.10.10
IGMP: Received v2 Report on INSIDE from 192.168.1.50 for 230.10.10.10  <-- IGMPv2 Report received
IGMP: group_db: add new group 230.10.10.10 on INSIDE
IGMP: MRIB updated (*,230.10.10.10) : Success
IGMP: Switching to EXCLUDE mode for 230.10.10.10 on INSIDE
IGMP: Updating EXCLUDE group timer for 230.10.10.10

流開始：

vlc_video_on

驗證（操作方案）

firepower# show capture
capture INSIDE type raw-data interface INSIDE [Buffer Full - 524156 bytes]    <-- Multicast packets on the egress interface
match ip host 192.168.103.60 host 230.10.10.10
capture OUTSIDE type raw-data trace interface OUTSIDE [Buffer Full - 524030 bytes]   <-- Multicast packets on the ingress interface
match ip host 192.168.103.60 host 230.10.10.10

防火牆的mroute表：

firepower# show mroute
Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group,
       C - Connected, L - Local, I - Received Source Specific Host Report,
       P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,
       J - Join SPT
Timers: Uptime/Expires
Interface state: Interface, State

(*, 230.10.10.10), 00:00:34/never, RP 0.0.0.0, flags: SCJ
  Incoming interface: Null
  RPF nbr: 0.0.0.0
  Immediate Outgoing interface list:
    INSIDE, Forward, 00:00:34/never

(192.168.103.60, 230.10.10.10), 00:01:49/00:03:29, flags: SFJT
  Incoming interface: OUTSIDE
  RPF nbr: 192.168.103.60
  Inherited Outgoing interface list:
    INSIDE, Forward, 00:00:34/never        <-- The OIL shows an interface

firepower# show mfib 230.10.10.10
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
             AR - Activity Required, K - Keepalive
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
Other counts: Total/RPF failed/Other drops
Interface Flags: A - Accept, F - Forward, NS - Negate Signalling
             IC - Internal Copy, NP - Not platform switched
             SP - Signal Present
Interface Counts: FS Pkt Count/PS Pkt Count

(*,230.10.10.10) Flags: C K
  Forwarding: 0/0/0/0, Other: 0/0/0
  INSIDE Flags: F NS
    Pkts: 0/0
(192.168.103.60,230.10.10.10) Flags: K
  Forwarding: 6373/0/1354/0, Other: 548/548/0      <-- There are multicast packets forwarded
  OUTSIDE Flags: A
  INSIDE Flags: F NS
    Pkts: 6373/6

mfib計數器：

firepower# show mfib count
IP Multicast Statistics
10 routes, 5 groups, 0.40 average sources per group
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kilobits per second
Other counts: Total/RPF failed/Other drops(OIF-null, rate-limit etc)
Group: 224.0.1.39
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 224.0.1.40
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 230.10.10.10
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
  Source: 192.168.103.60,
    Forwarding: 7763/0/1354/0, Other: 548/548/0   <-- There are multicast packets forwarded
  Tot. shown: Source count: 1, pkt count: 0
Group: 232.0.0.0/8
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
Group: 239.255.255.250
  RP-tree:
    Forwarding: 0/0/0/0, Other: 0/0/0
  Source: 192.168.1.50,
    Forwarding: 7/0/500/0, Other: 0/0/0
  Tot. shown: Source count: 1, pkt count: 0

IGMP窺探

IGMP監聽是交換器上使用的一種機制，用於防止多點傳播泛濫。
交換機監控IGMP報告，以確定主機（接收器）的位置。
交換機監控IGMP查詢，以確定路由器/防火牆（發件人）的位置。
大多數思科交換機預設啟用IGMP監聽。有關詳細資訊，請參閱相關交換指南。以下是L3 Catalyst交換器的輸出範例：

switch# show ip igmp snooping statistics

  Current number of Statistics entries    : 15
  Configured Statistics database limit    : 32000
  Configured Statistics database threshold: 25600
  Configured Statistics database limit    : Not exceeded
  Configured Statistics database threshold: Not exceeded

Snooping statistics for Vlan204
#channels: 3
#hosts   : 5

Source/Group                    Interface       Reporter        Uptime   Last-Join Last-Leave
0.0.0.0/230.10.10.10            Vl204:Gi1/48    192.168.1.50    2d13h        -     2d12h
0.0.0.0/230.10.10.10            Vl204:Gi1/48    192.168.1.97    2d13h    2d12h         -
0.0.0.0/230.10.10.10            Vl204:Gi2/1     192.168.1.50    2d10h    02:20:05  02:20:00
0.0.0.0/239.255.255.250         Vl204:Gi2/1     192.168.1.50    2d11h    02:20:05  02:20:00
0.0.0.0/239.255.255.250         Vl204:Gi2/1     192.168.2.50    2d14h    2d13h         -
0.0.0.0/239.255.255.250         Vl204:Gi2/1     192.168.6.50    2d13h        -     2d13h
0.0.0.0/224.0.1.40              Vl204:Gi2/26    192.168.2.1     2d14h    00:00:39  2d13h

Snooping statistics for Vlan206
#channels: 4
#hosts   : 3

Source/Group                    Interface       Reporter        Uptime   Last-Join Last-Leave
0.0.0.0/230.10.10.10            Vl206:Gi1/48    192.168.6.91    00:30:15 2d13h     2d13h
0.0.0.0/239.10.10.10            Vl206:Gi1/48    192.168.6.91    2d14h    2d13h         -
0.0.0.0/239.255.255.250         Vl206:Gi2/1     192.168.6.50    2d12h    00:52:49  00:52:45
0.0.0.0/224.0.1.40              Vl206:Gi2/26    192.168.6.1     00:20:10 2d13h     2d13h
0.0.0.0/230.10.10.10            Vl206:Gi2/26    192.168.6.1     2d13h    2d13h         -
0.0.0.0/230.10.10.10            Vl206:Gi2/26    192.168.6.91    2d13h        -     2d13h
0.0.0.0/239.10.10.10            Vl206:Gi2/26    192.168.6.1     2d14h    2d14h         -
0.0.0.0/239.10.10.10            Vl206:Gi2/26    192.168.6.91    2d14h        -     2d14h

任務3 - IGMP靜態組與IGMP加入組

概觀

	ip igmp static-group	ip igmp join-group
是否應用於FTD介面？	是	是
FTD是否會吸引多點傳播流？	是，將PIM加入傳送到上游裝置。源裝置或到集結點(RP)。僅當使用此命令的FTD是該介面上的PIM指定路由器(DR)時，才會發生這種情況。	是，將PIM加入傳送到上游裝置。源裝置或到集結點(RP)。僅當使用此命令的FTD是該介面上的PIM指定路由器(DR)時，才會發生這種情況。
FTD是否將多點傳播流量轉送出介面？	是	是
FTD會消耗並回覆多點傳播流量嗎	否	是，FTD將多點傳播流傳送到CPU、使用它，然後回覆來源。
CPU影響	最小，因為資料包未傳送到CPU。	可影響FTD CPU，因為屬於該組的每個多點傳送封包都會被傳送到FTD CPU。

任務要求

請考慮使用此拓樸：

igmp_snooping_topology

在防火牆上啟用以下擷取：

firepower# capture CAPI interface OUTSIDE trace match icmp host 192.168.103.62 any
firepower# capture CAPO interface INSIDE match icmp host 192.168.103.62 any

使用來自第3層交換器的ICMP ping將多點傳播流量傳送到IP 230.11.11.11，並檢查防火牆處理此問題的方式。
在防火牆INSIDE介面上啟用igmp static-group命令，並檢查防火牆如何處理組播流(IP 230.11.11.11)。
在防火牆INSIDE介面上啟用igmp static-group命令，並檢查防火牆如何處理組播流(IP 230.11.11.11)。

解決方案

防火牆沒有IP 230.11.11.11的任何路由：

firepower# show mroute

Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group,
       C - Connected, L - Local, I - Received Source Specific Host Report,
       P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,
       J - Join SPT
Timers: Uptime/Expires
Interface state: Interface, State

(*, 239.255.255.250), 00:43:21/never, RP 0.0.0.0, flags: SCJ
  Incoming interface: Null
  RPF nbr: 0.0.0.0
  Immediate Outgoing interface list:
    OUTSIDE, Forward, 00:05:41/never
    INSIDE, Forward, 00:43:21/never

測試多點傳送的簡單方法是使用ICMP ping工具。在這種情況下，從R2對組播IP地址230.11.11.11發起ping:

L3-Switch# ping 230.11.11.11 re 100
Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 230.11.11.11, timeout is 2 seconds:
...............................

在防火牆上，動態建立mroute且OIL為空：

firepower# show mroute

Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group,
C - Connected, L - Local, I - Received Source Specific Host Report,
P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,
J - Join SPT
Timers: Uptime/Expires
Interface state: Interface, State

(192.168.103.62, 230.11.11.11), 00:02:33/00:00:56, flags: SPF  <-- The mroute is added
  Incoming interface: OUTSIDE
  RPF nbr: 192.168.103.62
 Outgoing interface list: Null     <-- The OIL is empty

防火牆上的擷取顯示：

firepower# show capture
capture CAPI type raw-data trace interface OUTSIDE [Capturing - 1040 bytes]    <-- There are ICMP packets captured on ingress interface
match icmp host 192.168.103.62 any
capture CAPO type raw-data interface INSIDE [Capturing - 0 bytes]     <-- There are no ICMP packets on egress
match icmp host 192.168.103.62 any

防火牆會為每個ping建立連線，但會以靜默方式捨棄封包：

firepower# show log | include 230.11.11.11
May 17 2022 11:05:47: %FTD-7-609001: Built local-host identity:230.11.11.11       <-- A new connection is created
May 17 2022 11:05:47: %FTD-6-302020: Built inbound ICMP connection for faddr 192.168.1.99/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:47: %FTD-6-302020: Built inbound ICMP connection for faddr 192.168.103.62/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:49: %FTD-6-302021: Teardown ICMP connection for faddr 192.168.1.99/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:49: %FTD-6-302021: Teardown ICMP connection for faddr 192.168.103.62/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:49: %FTD-7-609002: Teardown local-host identity:230.11.11.11 duration 0:00:02  <-- The connection is closed
May 17 2022 11:05:51: %FTD-7-609001: Built local-host identity:230.11.11.11             <-- A new connection is created
May 17 2022 11:05:51: %FTD-6-302020: Built inbound ICMP connection for faddr 192.168.1.99/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:51: %FTD-6-302020: Built inbound ICMP connection for faddr 192.168.103.62/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:53: %FTD-6-302021: Teardown ICMP connection for faddr 192.168.1.99/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:53: %FTD-6-302021: Teardown ICMP connection for faddr 192.168.103.62/6 gaddr 230.11.11.11/0 laddr 230.11.11.11/0 type 8 code 0
May 17 2022 11:05:53: %FTD-7-609002: Teardown local-host identity:230.11.11.11 duration 0:00:02      <-- The connection is closed

注意：LINA ASP丟棄捕獲不會顯示丟棄的資料包

組播資料包丟棄的主要指示是：

firepower# show mfib
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
             AR - Activity Required, K - Keepalive
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
Other counts: Total/RPF failed/Other drops
Interface Flags: A - Accept, F - Forward, NS - Negate Signalling
             IC - Internal Copy, NP - Not platform switched
             SP - Signal Present
Interface Counts: FS Pkt Count/PS Pkt Count

(*,224.0.1.39) Flags: S K
  Forwarding: 0/0/0/0, Other: 0/0/0
(*,224.0.1.40) Flags: S K
  Forwarding: 0/0/0/0, Other: 0/0/0
(192.168.103.62,230.11.11.11) Flags: K         <-- The multicast stream
  Forwarding: 0/0/0/0, Other: 27/27/0          <-- The packets are dropped

igmp static-group

在FMC上配置靜態IGMP組：

igmp_static_config

下面是後台部署的內容：

interface Port-channel1.205
 vlan 205
 nameif INSIDE
 cts manual
  propagate sgt preserve-untag
  policy static sgt disabled trusted
 security-level 0
 ip address 192.168.1.24 255.255.255.0
 igmp static-group 230.11.11.11        <-- IGMP static group is enabled on the interface

ping失敗，但ICMP多點傳播流量現在通過防火牆轉送：

L3-Switch# ping 230.11.11.11 re 10000
Type escape sequence to abort.
Sending 10000, 100-byte ICMP Echos to 230.11.11.11, timeout is 2 seconds:
............................

firepower# show capture
capture CAPI type raw-data trace interface OUTSIDE [Capturing - 650 bytes]   <-- ICMP packets are captured on ingress interface
match icmp host 192.168.103.62 any
capture CAPO type raw-data interface INSIDE [Capturing - 670 bytes]    <-- ICMP packets are captured on egress interface
match icmp host 192.168.103.62 any

firepower# show capture CAPI
8 packets captured

1: 11:31:32.470541 192.168.103.62 > 230.11.11.11 icmp: echo request
2: 11:31:34.470358 192.168.103.62 > 230.11.11.11 icmp: echo request
3: 11:31:36.470831 192.168.103.62 > 230.11.11.11 icmp: echo request
4: 11:31:38.470785 192.168.103.62 > 230.11.11.11 icmp: echo request
...

firepower# show capture CAPO
11 packets captured

1: 11:31:32.470587 802.1Q vlan#205 P0 192.168.103.62 > 230.11.11.11 icmp: echo request
2: 11:31:34.470404 802.1Q vlan#205 P0 192.168.103.62 > 230.11.11.11 icmp: echo request
3: 11:31:36.470861 802.1Q vlan#205 P0 192.168.103.62 > 230.11.11.11 icmp: echo request
4: 11:31:38.470816 802.1Q vlan#205 P0 192.168.103.62 > 230.11.11.11 icmp: echo request

注意：資料包的跟蹤顯示不正確的輸出（輸入介面與輸出相同）。如需更多詳細資訊，請檢查Cisco錯誤ID CSCvm89673。

firepower# show capture CAPI packet-number 1 trace

1: 11:39:33.553987 192.168.103.62 > 230.11.11.11 icmp: echo request
Phase: 1
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 3172 ns
Config:
Additional Information:
MAC Access list

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 3172 ns
Config:
Implicit Rule
Additional Information:
MAC Access list

Phase: 3
Type: ROUTE-LOOKUP
Subtype: No ECMP load balancing
Result: ALLOW
Elapsed time: 9760 ns
Config:
Additional Information:
Destination is locally connected. No ECMP load balancing.
Found next-hop 192.168.103.62 using egress ifc OUTSIDE(vrfid:0)

Phase: 4
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 5368 ns
Config:
Implicit Rule
Additional Information:

Phase: 5
Type: CONN-SETTINGS
Subtype:
Result: ALLOW
Elapsed time: 5368 ns
Config:
class-map class-default
match any
policy-map global_policy
class class-default
set connection advanced-options UM_STATIC_TCP_MAP
service-policy global_policy global
Additional Information:

Phase: 6
Type: NAT
Subtype: per-session
Result: ALLOW
Elapsed time: 5368 ns
Config:
Additional Information:

Phase: 7
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Elapsed time: 5368 ns
Config:
Additional Information:

Phase: 8
Type: CLUSTER-REDIRECT
Subtype: cluster-redirect
Result: ALLOW
Elapsed time: 31720 ns
Config:
Additional Information:

Phase: 9
Type: INSPECT
Subtype: np-inspect
Result: ALLOW
Elapsed time: 488 ns
Config:
class-map inspection_default
match default-inspection-traffic
policy-map global_policy
class inspection_default
inspect icmp
service-policy global_policy global
Additional Information:

Phase: 10
Type: INSPECT
Subtype: np-inspect
Result: ALLOW
Elapsed time: 2440 ns
Config:
Additional Information:

Phase: 11
Type: MULTICAST    <-- The packet is multicast
Subtype:
Result: ALLOW
Elapsed time: 976 ns
Config:
Additional Information:

Phase: 12
Type: FLOW-CREATION    <-- A new flow is created
Subtype:
Result: ALLOW
Elapsed time: 56120 ns
Config:
Additional Information:
New flow created with id 5690, packet dispatched to next module

Phase: 13
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 10248 ns
Config:
Additional Information:
MAC Access list

Result:
input-interface: OUTSIDE(vrfid:0)
input-status: up
input-line-status: up
output-interface: OUTSIDE(vrfid:0)
output-status: up
output-line-status: up
Action: allow       <-- The packet is allowed
Time Taken: 139568 ns

提示：可以從源主機使用超時0執行ping，也可以檢查防火牆mfib計數器：

L3-Switch# ping 230.11.11.11 re 500 timeout 0
Type escape sequence to abort.
Sending 1000, 100-byte ICMP Echos to 230.11.11.11, timeout is 0 seconds:
......................................................................
......................................................................
......................................................................
....................

firepower# clear mfib counters
firepower# !ping from the source host. 

firepower# show mfib 230.11.11.11
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
AR - Activity Required, K - Keepalive
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
Other counts: Total/RPF failed/Other drops
Interface Flags: A - Accept, F - Forward, NS - Negate Signalling
IC - Internal Copy, NP - Not platform switched
SP - Signal Present
Interface Counts: FS Pkt Count/PS Pkt Count

(*,230.11.11.11) Flags: C K
  Forwarding: 0/0/0/0, Other: 0/0/0
  INSIDE Flags: F NS
    Pkts: 0/0
(192.168.103.62,230.11.11.11) Flags: K
  Forwarding: 500/0/100/0, Other: 0/0/0    <-- 500 multicast packets forwarded. The average size of each packet is 100 Bytes
  OUTSIDE Flags: A
  INSIDE Flags: F NS
    Pkts: 500/0

igmp join-group

在FMC遠端交換機上，配置先前配置的靜態組配置並配置IGMP加入組：

igmp_join_config

igmp_join_topology

部署的配置：

firepower# show run interface Port-channel1.205
!
interface Port-channel1.205
vlan 205
nameif INSIDE
cts manual
propagate sgt preserve-untag
policy static sgt disabled trusted
security-level 0
ip address 192.168.1.24 255.255.255.0
igmp join-group 230.11.11.11       <-- The interface joined the multicast group

IGMP組：

firepower# show igmp group
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
230.11.11.11 INSIDE 00:30:43 never 192.168.1.24   <-- The group is enabled on the interface

在來源主機中，嘗試對230.11.11.11 IP進行第一個ICMP多點傳送測試：

L3-Switch# ping 230.11.11.11 repeat 10
Type escape sequence to abort.
Sending 10, 100-byte ICMP Echos to 230.11.11.11, timeout is 2 seconds:

Reply to request 0 from 192.168.1.24, 12 ms
Reply to request 1 from 192.168.1.24, 8 ms
Reply to request 2 from 192.168.1.24, 8 ms
Reply to request 3 from 192.168.1.24, 8 ms
Reply to request 4 from 192.168.1.24, 8 ms
Reply to request 5 from 192.168.1.24, 12 ms
Reply to request 6 from 192.168.1.24, 8 ms
Reply to request 7 from 192.168.1.24, 8 ms
Reply to request 8 from 192.168.1.24, 8 ms
Reply to request 9 from 192.168.1.24, 8 ms

註：如果您沒有看到所有回覆，請檢查Cisco錯誤ID CSCvm90069。

任務4 — 配置IGMP Stub組播路由

stub_topology

在FTD上設定存根多點傳送路由，以便將INSIDE介面上收到的IGMP成員身份報告訊息轉送到OUTSIDE介面。

解決方案

部署的配置：

firepower# show run multicast-routing
multicast-routing               <-- Multicast routing is enabled
firepower# show run interface Port-channel1.205
!
interface Port-channel1.205
 vlan 205
 nameif INSIDE
 cts manual
  propagate sgt preserve-untag
  policy static sgt disabled trusted
 security-level 0
 ip address 192.168.1.24 255.255.255.0
 igmp forward interface OUTSIDE        <-- The interface does stub multicast routing

驗證

在FTD上啟用擷取：

firepower# capture CAPI interface INSIDE trace match igmp any host 230.10.10.10
firepower# capture CAPO interface OUTSIDE match igmp any host 230.10.10.10

驗證

要強制IGMP成員報告，您可以使用類似VLC的應用程式：

vlc_play_ip_stream

FTD代理IGMP封包：

firepower# show capture
capture CAPI type raw-data trace interface INSIDE [Capturing - 66 bytes]  <-- IGMP packets captured on ingress
match igmp any host 230.10.10.10
capture CAPO type raw-data interface OUTSIDE [Capturing - 62 bytes]   <-- IGMP packets captured on egress
match igmp any host 230.10.10.10

FTD會變更來源IP:

firepower# show capture CAPI

1 packet captured

   1: 12:21:12.820483 802.1Q vlan#205 P6 192.168.1.50 > 230.10.10.10 ip-proto-2, length 8    <-- The source IP of the packet on ingress interface
1 packet shown
firepower# show capture CAPO

1 packet captured

   1: 12:21:12.820743 192.168.103.91 > 230.10.10.10 ip-proto-2, length 8  <-- The source IP of the packet on egress interface
1 packet shown

如果您在Wireshark中檢查pcap，可以看到該資料包完全由防火牆重新生成（IP標識更改）。

在FTD上建立一個組專案：

firepower# show igmp group
IGMP Connected Group Membership
Group Address    Interface            Uptime    Expires   Last Reporter
230.10.10.10     INSIDE               00:15:22  00:03:28  192.168.1.50     <-- IGMP group is enabled on the ingress interface
239.255.255.250  INSIDE               00:15:27  00:03:29  192.168.1.50

FTD防火牆建立2個控制平面連線：

firepower# show conn all address 230.10.10.10
9 in use, 28 most used
Inspect Snort:
preserve-connection: 0 enabled, 0 in effect, 0 most enabled, 0 most in effect
IGMP INSIDE 192.168.1.50 NP Identity Ifc 230.10.10.10, idle 0:00:09, bytes 8, flags          <-- Connection terminated on the ingress interface
IGMP OUTSIDE 230.10.10.10 NP Identity Ifc 192.168.103.91, idle 0:00:09, bytes 8, flags       <-- Connection terminated on the egress interface

第一個封包的追蹤軌跡：

firepower# show capture CAPI packet-number 1 trace

6 packets captured

1: 12:21:12.820483 802.1Q vlan#205 P6 192.168.1.50 > 230.10.10.10 ip-proto-2, length 8   <-- The first packet of the flow
Phase: 1
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 5124 ns
Config:
Additional Information:
MAC Access list

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 5124 ns
Config:
Implicit Rule
Additional Information:
MAC Access list

Phase: 3
Type: ROUTE-LOOKUP
Subtype: No ECMP load balancing
Result: ALLOW
Elapsed time: 7808 ns
Config:
Additional Information:
Destination is locally connected. No ECMP load balancing.
Found next-hop 192.168.1.50 using egress ifc INSIDE(vrfid:0)

Phase: 4
Type: CLUSTER-DROP-ON-SLAVE
Subtype: cluster-drop-on-slave
Result: ALLOW
Elapsed time: 5368 ns
Config:
Additional Information:

Phase: 5
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Elapsed time: 5368 ns
Config:
Implicit Rule
Additional Information:

Phase: 6
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Elapsed time: 5368 ns
Config:
Additional Information:

Phase: 7
Type: NAT
Subtype: per-session
Result: ALLOW
Elapsed time: 5368 ns
Config:
Additional Information:

Phase: 8
Type: CLUSTER-REDIRECT
Subtype: cluster-redirect
Result: ALLOW
Elapsed time: 40504 ns
Config:
Additional Information:

Phase: 9
Type: MULTICAST        <-- The packet is multicast
Subtype:
Result: ALLOW
Elapsed time: 976 ns
Config:
Additional Information:

Phase: 10
Type: FLOW-CREATION       <-- A new flow is created
Subtype:
Result: ALLOW
Elapsed time: 17568 ns
Config:
Additional Information:
New flow created with id 5945, packet dispatched to next module

Phase: 11
Type: FLOW-CREATION      <-- A second flow is created
Subtype:
Result: ALLOW
Elapsed time: 39528 ns
Config:
Additional Information:
New flow created with id 5946, packet dispatched to next module

Phase: 12
Type: NEXTHOP-LOOKUP-FROM-OUTPUT-ROUTE-LOOKUP
Subtype: Lookup Nexthop on interface
Result: ALLOW
Elapsed time: 6344 ns
Config:
Additional Information:
Found next-hop 230.10.10.10 using egress ifc OUTSIDE(vrfid:0)

Phase: 13
Type: CAPTURE
Subtype:
Result: ALLOW
Elapsed time: 9760 ns
Config:
Additional Information:
MAC Access list

Result:
input-interface: INSIDE(vrfid:0)
input-status: up
input-line-status: up
output-interface: INSIDE(vrfid:0)
output-status: up
output-line-status: up
Action: allow
Time Taken: 154208 ns

已知的問題

在目的地區域過濾多點傳送流量

無法為與組播流量匹配的訪問控制策略規則指定目標安全區域：

acp_misconfig

FMC使用手冊中也有相關說明：

fmc_config_guide

超過IGMP介面限制時，防火牆會拒絕IGMP報告

預設情況下，防火牆允許介面上最多有500個當前活動聯接（報告）。如果超出此閾值，防火牆將忽略來自組播接收器的其他傳入IGMP報告。

要檢查IGMP限制和活動聯接，請運行命令show igmp interface nameif:

asa# show igmp interface inside
inside is up, line protocol is up
  Internet address is 10.10.10.1/24
  IGMP is enabled on interface
  Current IGMP version is 2
  IGMP query interval is 125 seconds
  IGMP querier timeout is 255 seconds
  IGMP max query response time is 10 seconds
  Last member query response interval is 1 seconds
  Inbound IGMP access group is:   
  IGMP limit is 500, currently active joins: 500
  Cumulative IGMP activity: 0 joins, 0 leaves
  IGMP querying router is 10.10.10.1 (this system)

IGMP debug指令debug igmp 顯示以下輸出：

asa# debug igmp
Apr 20 2023 09:37:10: %ASA-7-711001: IGMP: Group 230.1.2.3 limit denied on inside

修正了思科錯誤ID CSCvw60976的軟體版本允許使用者為每個介面配置最多5000個組。

防火牆忽略232.x.x.x/8地址範圍的IGMP報告

232.x.x.x/8位址範圍用於來源特定多點傳送(SSM)。防火牆不支援PIM源特定組播(SSM)功能和相關配置。

IGMP debug指令debug igmp 顯示以下輸出：

asa# debug igmp
Apr 20 2023 09:37:10: %ASA-7-711001: IGMP: Received v2 Report on inside from 10.10.10.11 for 232.179.89.253
Apr 20 2023 09:37:10: %ASA-7-711001: IGMP: group_db: add new group 232.179.89.253 on inside
Apr 20 2023 09:37:10: %ASA-7-711001: IGMP: Exclude report on inside ignored for SSM group 232.179.89.253

思科錯誤ID CSCsr53916 跟蹤增強功能以支援SSM範圍。

Firepower威脅防禦IGMP和組播基礎知識故障排除

下載選項

無偏見用語

關於此翻譯

目錄

簡介

必要條件

需求

採用元件

背景資訊

設定

IGMP基礎知識

任務1 — 控制平面組播流量

任務2 — 配置基本組播

IGMP窺探

任務3 - IGMP靜態組與IGMP加入組

igmp static-group

igmp join-group

任務4 — 配置IGMP Stub組播路由

已知的問題

在目的地區域過濾多點傳送流量

超過IGMP介面限制時，防火牆會拒絕IGMP報告

防火牆忽略232.x.x.x/8地址範圍的IGMP報告

相關資訊

修訂記錄

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