Uma das duas máquinas na mesma rede não recebe membros do grupo de multicast

Question

na rede remota, temos duas máquinas. um deles recebe assinaturas multicast, outro não faz

a máquina 1 recebe apenas a consulta do igmp:

sudo tcpdump -nevv -i eth1 -s 1515 igmp
tcpdump: listening on eth1, link-type EN10MB (Ethernet), capture size 1515 bytes
09:42:12.973995 00:24:97:23:54:3f > 01:00:5e:00:00:01, ethertype IPv4 (0x0800), length 60: (tos 0xc0, ttl 1, id 13227, offset 0, flags [none], proto IGMP (2), length 32, options (RA))
    157.157.7.252 > 224.0.0.1: igmp query v2

enquanto a máquina dois recebe muito mais pacotes igmp:

09:46:12.986376 00:24:97:23:54:3f > 01:00:5e:00:00:01, ethertype IPv4 (0x0800), length 60: (tos 0xc0, ttl 1, id 13468, offset 0, flags [none], proto IGMP (2), length 32, options (RA))
    157.157.7.252 > 224.0.0.1: igmp query v2
09:46:13.148086 00:e0:81:b3:f7:66 > 01:00:5e:14:14:8b, ethertype IPv4 (0x0800), length 46: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
    192.168.21.12 > 230.20.20.139: igmp v2 report 230.20.20.139
09:46:13.384097 00:e0:81:b3:f7:66 > 01:00:5e:1e:1e:6e, ethertype IPv4 (0x0800), length 46: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
    192.168.21.12 > 231.30.30.110: igmp v2 report 231.30.30.110
09:46:15.056105 00:e0:81:b3:f7:66 > 01:00:5e:14:14:b7, ethertype IPv4 (0x0800), length 46: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
    192.168.21.12 > 231.20.20.183: igmp v2 report 231.20.20.183
09:46:15.212094 00:e0:81:b3:f7:66 > 01:00:5e:00:00:fb, ethertype IPv4 (0x0800), length 46: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
    192.168.21.12 > 224.0.0.251: igmp v2 report 224.0.0.251
09:46:15.900096 00:e0:81:b3:f7:66 > 01:00:5e:14:14:24, ethertype IPv4 (0x0800), length 46: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
    192.168.21.12 > 230.20.20.36: igmp v2 report 230.20.20.36
09:46:16.036096 00:e0:81:b3:f7:66 > 01:00:5e:1d:1d:99, ethertype IPv4 (0x0800), length 46: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
    192.168.21.12 > 231.29.29.153: igmp v2 report 231.29.29.153
09:46:18.764102 00:e0:81:b3:f7:66 > 01:00:5e:14:14:8a, ethertype IPv4 (0x0800), length 46: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
    192.168.21.12 > 230.20.20.138: igmp v2 report 230.20.20.138
09:46:21.612091 00:e0:81:b3:f7:66 > 01:00:5e:14:14:08, ethertype IPv4 (0x0800), length 46: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
    192.168.21.12 > 231.20.20.8: igmp v2 report 231.20.20.8
09:46:22.764102 00:e0:81:b3:f7:66 > 01:00:5e:14:14:70, ethertype IPv4 (0x0800), length 46: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
    192.168.21.12 > 230.20.20.112: igmp v2 report 230.20.20.112
09:46:22.956111 00:e0:81:b3:f7:66 > 01:00:5e:14:14:85, ethertype IPv4 (0x0800), length 46: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
    192.168.21.12 > 230.20.20.133: igmp v2 report 230.20.20.133

em ambos os casos, as rotas são:

224.0.0.0       *               240.0.0.0       U     0      0        0

mesmo lan, sem firewalls, sem regras de iptables, e funcionou bem antes do fracasso de ups ..

máquina não funciona é o ubuntu 14, trabalhando um é debian jessie

tentei testar com iperf, a máquina ubuntu pode enviar pacotes multicast mas não pode recebê-los.

o que mais poderia ser verificado?

    

Answer 1

mude para o IGMPv2 no Ubuntu

echo "2" > /proc/sys/net/ipv4/conf/eth1/force_igmp_version

e tente novamente. Se você tiver o mesmo problema que verificar a filtragem de caminho inverso

cat /proc/sys/net/ipv4/conf/default/rp_filter

1 indica que o kernel fará a validação da fonte confirmando     caminho inverso.

0 indica, nenhuma validação de fonte.

use 0