Q25Services
Refer to the exhibit. A network administrator is deploying IGMP to enable transmission of the multicast feed to the receiver. Which configuration must be deployed on GW1 to allow IGMP joins only for the assigned (S, G) feed?
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3
Answer is correct, and it is worth reading why the two entries are needed.
https://content.cisco.com/chapter.sjs?uri=%2Fsearchable%2Fchapter%2Fcontent%2Fen%2Fus%2Ftd%2Fdocs%2Fios-xml%2Fios%2Fipmulti%2Fcommand%2Fimc-cr-book%2Fimc_i1.html.xml#wp9202555670
"Specifically, if an IGMP report with (S1, S2...Sn, G) is received, first the group (0, G) is checked against the access list statements. If the group is denied, the entire IGMP report is denied. If the group is permitted, each individual (S, G) pair is checked against the access list. Denied sources are taken out of the IGMP report, thereby denying any sources that match the access list from sending to the group."
C 2
Selected Answer: C
config t
access-list 100 permit igmp host 0.0.0.0 host 239.10.10.10
access-list 100 permit igmp host 172.20.20.3 host 239.10.10.10
access-list 100 deny igmp any any
interface GigabitEthernet1
ip igmp access-group 100
ip igmp version 3
end