Is it possible to get a traffic from a multicast address with specific destination port using IGMP? For example, I have some multicast flows like 184.108.40.206:5000, 220.127.116.11:5001 to 18.104.22.168:5009. Is there any way that I can request only the traffic from a specific port - for example only from 22.214.171.124:5000 ?
Is it possible to get a traffic from a multicast address with specific destination port using IGMP?
You have three decent choices:
- Ask some senders / listeners to change their group
- Deploy IGMPv3 with PIM-SSM
- Deny certain UDP ports with an extended ACL (example: the Catalyst 4500 calls this a Port ACL... since it requires manual intervention for each host, this is not very scalable, and switch port ACLs are only supported on certain switching platforms)
Strictly speaking, no an IGMPv2 or IGMPv3 listener cannot specify a port to listen for. Let's assume you have the following situation:
- Source at 172.16.1.50 sends to 126.96.36.199:5000
- Source at 172.16.1.51 sends to 188.8.131.52:5001
- Source at 172.16.1.59 sends to 184.108.40.206:5009
PIM SSM / IGMPv3 include the ability to EXCLUDE certain source IP addresses. This means an IGMPv3 listener can exclude one or more of the source IPs; for instance, a IGMPv3 listener can exclude listening for 172.16.1.59.
Speaking practically, this is a design problem. When someone allocated 220.127.116.11 for multicast (presumably using IGMPv2 and PIM-SPARSE or PIM-DENSE) in your network, they should not have given that same group address to multiple applications. The simplest way around this problem is to change the group for one application and continue using IGMPv2.
If you don't have someone coordinating multicast addresses, then consider this a good reason to start doing so. There are ways to control who sends what multicast between subnets (at least in Cisco IOS). As organizations expand their use of multicast, controlling who sends what is pretty important.