L'IGMP c'est du multicast. Je ne dis pas c'est la bonne façon de faire.
sudo tcpdump -i eth0.100 -vv :
18:05:24.301520 IP (tos 0xe0, ttl 63, id 18215, offset 0, flags [none], proto UDP (17), length 73)
176-144-x-y.abo.bbox.fr.49153 > nsabo1.bouyguesbox.fr.domain: [udp sum ok] 22826+ AAAA? time-a.timefreq.bld
18:05:24.301804 IP (tos 0xe0, ttl 63, id 58154, offset 0, flags [none], proto UDP (17), length 73)
176-144-x-y.abo.bbox.fr.49153 > nsabo2.bouyguesbox.fr.domain: [udp sum ok] 22826+ AAAA? time-a.timefreq.bld
18:05:24.304727 IP (tos 0x80, ttl 250, id 18215, offset 0, flags [none], proto UDP (17), length 147)
nsabo1.bouyguesbox.fr.domain > 176-144-x-y.abo.bbox.fr.49153: [udp sum ok] 22826 q: AAAA? time-a.timefreq.b
18:05:24.741020 IP (tos 0x0, ttl 64, id 10175, offset 0, flags [DF], proto UDP (17), length 73)
176-144-x-y.abo.bbox.fr.57386 > nsabo1.bouyguesbox.fr.domain: [udp sum ok] 44375+ PTR? 22.124.144.176.in-ad
18:05:24.745689 IP (tos 0x80, ttl 59, id 11531, offset 0, flags [none], proto UDP (17), length 113)
nsabo1.bouyguesbox.fr.domain > 176-144-x-y.abo.bbox.fr.57386: [udp sum ok] 44375 q: PTR? 22.124.144.176.in-
18:05:24.747107 IP (tos 0x0, ttl 64, id 10176, offset 0, flags [DF], proto UDP (17), length 73)
176-144-x-y.abo.bbox.fr.55454 > nsabo1.bouyguesbox.fr.domain: [udp sum ok] 19980+ PTR? 10.122.158.194.in-ad
18:05:24.750805 IP (tos 0x80, ttl 250, id 10176, offset 0, flags [none], proto UDP (17), length 108)
nsabo1.bouyguesbox.fr.domain > 176-144-x-y.abo.bbox.fr.55454: [udp sum ok] 19980 q: PTR? 10.122.158.194.in-
18:05:24.752067 IP (tos 0x0, ttl 64, id 10177, offset 0, flags [DF], proto UDP (17), length 73)
176-144-x-y.abo.bbox.fr.41881 > nsabo1.bouyguesbox.fr.domain: [udp sum ok] 2766+ PTR? 15.122.158.194.in-add
18:05:24.755300 IP (tos 0x80, ttl 59, id 16779, offset 0, flags [none], proto UDP (17), length 108)
nsabo1.bouyguesbox.fr.domain > 176-144-x-y.abo.bbox.fr.41881: [udp sum ok] 2766 q: PTR? 15.122.158.194.in-a
18:05:25.714798 IP (tos 0x0, ttl 63, id 0, offset 0, flags [DF], proto TCP (6), length 107)
176-144-x-y.abo.bbox.fr.51231 > 216.218.230.212.8002: Flags [P.], cksum 0xde4e (correct), seq 3379178099:33
18:05:25.779126 IP (tos 0x0, ttl 64, id 10217, offset 0, flags [DF], proto UDP (17), length 74)
176-144-x-y.abo.bbox.fr.34928 > nsabo1.bouyguesbox.fr.domain: [udp sum ok] 12867+ PTR? 212.230.218.216.in-a
18:05:25.811980 IP (tos 0x80, ttl 59, id 11597, offset 0, flags [none], proto UDP (17), length 131)
- ll 1/289 0%
sudo tcpdump -i eth0.100 -n igmp
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0.100, link-type EN10MB (Ethernet), capture size 262144 bytes
18:35:47.998797 IP 176.144.x-y > 224.0.0.2: igmp leave 232.0.64.206
18:35:48.027114 IP 176.144.x-y > 232.0.64.206: igmp v2 report 232.0.64.206
18:35:55.617146 IP 176.144.x-y > 232.0.64.206: igmp v2 report 232.0.64.206
18:36:05.217166 IP 176.144.x-y > 232.0.64.206: igmp v2 report 232.0.64.206
18:36:15.723767 IP 0.0.0.0 > 224.0.0.1: igmp query v2
18:36:16.357129 IP 176.144.x-y > 239.255.250.250: igmp v2 report 239.255.250.250
18:36:18.817128 IP 176.144.x-y > 233.89.188.1: igmp v2 report 233.89.188.1
18:36:20.177140 IP 176.144.x-y > 239.255.255.250: igmp v2 report 239.255.255.250
18:36:21.857131 IP 176.144.x-y > 239.255.3.22: igmp v2 report 239.255.3.22
18:36:24.417127 IP 176.144.x-y > 239.255.255.246: igmp v2 report 239.255.255.246
18:36:24.417271 IP 176.144.x-y > 232.0.64.206: igmp v2 report 232.0.64.206
^C
11 packets captured
11 packets received by filter
0 packets dropped by kernel