Symptom

after a period of time, the "show ip igmp snooping" and "show ip igmp snooping detail"outputs change to empty like below: before problem: Switch(config-vlan-config)# show ip igmp snooping querier Vlan IP Address Version Expires Port 1 100.1.1.1 v3 00:03:58 port-channel100 Switch querier after a period of time: Switch(config-vlan-config)# show ip igmp snooping querier Vlan IP Address Version Expires Port Switch(config-vlan-config)#

Conditions

the problem always appear at the first time when we config the igmp snooping querier. disable and re-enable igmp snooping querier could resolve the issue. below is one of the repro steps: At first time ,I configure the querier, there is something in show output. I removed the configuration and tried what customer did. 1,add a ACL on SVI. 2,configure the querier. At first , there is data in output of ?show ip igmp snooping querier?, but it disappeared later. 3, reconfigured it output of show command get back. Debug was on in all progress. You can pay attention to the output on device F340.23.04-7700-1 Furthermore, we check the "show ip igmp snooping querier detail"especially, nothing displayed too. Relate log: F340.23.04-7700-1(config-vlan-config)# show ip igmp snooping querier Vlan IP Address Version Expires Port 1 100.1.1.1 v3 00:03:58 port-channel100 Switch querier F340.23.04-7700-1(config-vlan-config)# F340.23.04-7700-1(config-vlan-config)# 2016 %SYSLOG-4-SYSTEM_MSG : Certain/All debug element(s) for igmp is enabled for a long period in VTY: /dev/ttyS0! 2016 Nov 6 19:24:51.691299 igmp: SN: Flooding the packet to (iif Po100), came from cfs 2016 Nov 6 19:24:51.691528 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 Nov 6 19:24:51.691758 igmp: SN: Ignoring Query packet that came with configured snoop querier address. 2016 Nov 6 19:24:51.691835 igmp: SN: Flooding the packet to (iif Po100). 2016 Nov 6 19:24:51.691956 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 Nov 6 19:26:56.694142 igmp: SN: Querier timer expired. 2016 Nov 6 19:26:56.699923 igmp: SN: Ignoring Query packet that came with configured snoop querier address. 2016 Nov 6 19:26:56.700005 igmp: SN: Flooding the packet to (iif Po100), came from cfs 2016 Nov 6 19:26:56.700207 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 Nov 6 19:26:56.700429 igmp: SN: Ignoring Query packet that came with configured snoop querier address. 2016 Nov 6 19:26:56.700519 igmp: SN: Flooding the packet to (iif Po100). 2016 Nov 6 19:26:56.700639 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 Nov 6 19:29:01.708859 igmp: SN: Ignoring Query packet that came with configured snoop querier address. 2016 Nov 6 19:29:01.708928 igmp: SN: Flooding the packet to (iif Po100), came from cfs 2016 Nov 6 19:29:01.709165 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 Nov 6 19:29:01.709390 igmp: SN: Ignoring Query packet that came with configured snoop querier address. 2016 Nov 6 19:29:01.709467 igmp: SN: Flooding the packet to (iif Po100). 2016 Nov 6 19:29:01.709587 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 Nov 6 19:31:06.717607 igmp: SN: Ignoring Query packet that came with configured snoop querier address. 2016 Nov 6 19:31:06.717675 igmp: SN: Flooding the packet to (iif Po100), came from cfs 2016 Nov 6 19:31:06.717907 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 Nov 6 19:31:06.718131 igmp: SN: Ignoring Query packet that came with configured snoop querier address. 2016 Nov 6 19:31:06.718215 igmp: SN: Flooding the packet to (iif Po100). 2016 Nov 6 19:31:06.718336 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 Nov 6 19:33:11.729474 igmp: SN: Ignoring Query packet that came with configured snoop querier address. 2016 Nov 6 19:33:11.729541 igmp: SN: Flooding the packet to (iif Po100), came from cfs 2016 Nov 6 19:33:11.729766 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 Nov 6 19:33:11.730044 igmp: SN: Ignoring Query packet that came with configured snoop querier address. 2016 Nov 6 19:33:11.730125 igmp: SN: Flooding the packet to (iif Po100). 2016 Nov 6 19:33:11.730245 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 %SYSLOG-4-SYSTEM_MSG : Certain/All debug element(s) for igmp is enabled for a long period in VTY: /dev/ttyS0! 2016 Nov 6 19:35:16.745375 igmp: SN: Flooding the packet to (iif Po100), came from cfs 2016 Nov 6 19:35:16.745604 igmp: SN: Forwarding to internal SVI Vlan1 () 2016 Nov 6 19:35:16.745883 igmp: SN: Ignoring Query packet that came with configured snoop querier address. 2016 Nov 6 19:35:16.745963 igmp: SN: Flooding the packet to (iif Po100). 2016 Nov 6 19:35:16.746083 igmp: SN: Forwarding to internal SVI Vlan1 () F340.23.04-7700-1(config-vlan-config)# show ip igmp snooping querier Vlan IP Address Version Expires Port F340.23.04-7700-1(config-vlan-config)#

Workaround

disable and re-enable igmp snooping querier could resolve the issue.

Further Problem Description