Linux 7 Multicast Configuration
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Internal
Concepts
Procedure
Multicast at Kernel Level
Make sure multicast is enabled at kernel level.
To compile multicast support into the kernel, CONFIG_IP_MULTICAST must be present in the kernel configuration file.
Multicast Support at Interface Level
- Verify that the network interface you plan to use for multicast traffic has multicast enabled, and if not, turn it on.
- Configure multicast routing: Configure Multicast Routing
- If iptables runs on the system, allow multicast traffic for the interface that will handle multicast traffic: Configure iptables to allow Multicast
- Test it. For more details see the Troubleshooting section.
/proc
/proc/net/dev_mcast
Contains Layer2 multicast groups which a device is listening to (interface index, label, number of references, number of bound addresses).
/proc/net/igmp
Contains IPv4 multicast groups joined by this host.
/proc/net/igmp6
Contains IPv6 multicast groups joined by this host.
Troubleshooting
Display Multicast Group Membership Information
netstat -g
displays multicast group membership information for IPv4 and IPv6. Optionally use -n to prevent DNS lookups (faster).
The same information can be obtained from /proc:
cat /proc/net/dev_mcast cat /proc/net/igmp cat /proc/net/igmp6
For more details on these files see [#.2Fproc|/proc]] above.
Ping
Send Multicast Traffic
See
Organizatorium
TODO http://lartc.org/howto/lartc.multicast.html
echo 1 > /proc/sys/net/ipv4/ip_forward