Hello,
I'm setting up a small network to connect thrree disparate networks. Two of the networks are on the same subnet so we want to use NAT to hide the local IPs of those networks. I have NAT working and I can ping from each network to the others. Other IP traffic works as well. The problem I'm seeming to have is that I can't get multicast to NAT.
Network A is the network I'm sending mulicast traffic from. Router A is directly connected to Network A (vlan 1 at 10.0.0.1). Network B is the network I want to see the multicast traffic on. Router B is directly connected to Network B (vlan 1 at 10.0.0.1). Router A and B are directly connected to Network X (A is FE/4 at 10.10.10.1 and B is FE/4 at 10.10.10.2). See attached image. Router A NATs 10.0.0.0 to 10.1.0.0 and Router B NATs 10.0.0.0 to 10.2.0.0 (lots of "ip nat inside source static 10.0.0.38 10.2.0.38" commands). I have "ip pim dense-mode" on vlan 1 and F/4 on both routers. Both routers are running IOS 15.0(1)M9 and both are licensed for IP advanced services.
If I send a multicast packet from a system on network A with a TTL of 16, router B seems to block it because the RPF check fails:
rtr_b#show ip mfib 239.1.2.3 verbose
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
ET - Data Rate Exceeds Threshold, K - Keepalive
DDE - Data Driven Event, HW - Hardware Installed
I/O Item Flags: IC - Internal Copy, NP - Not platform switched,
NS - Negate Signalling, SP - Signal Present,
A - Accept, F - Forward, RA - MRIB Accept, RF - MRIB Forward
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
Other counts: Total/RPF failed/Other drops
I/O Item Counts: FS Pkt Count/PS Pkt Count
Default
(*,239.1.2.3) Flags: C K
SW Forwarding: 0/0/0/0, Other: 0/0/0
FastEthernet4 Flags: RF F NS
CEF: Adjacency with MAC: 01005E010203D867D9BA4FEA0800
Pkts: 0/0
Vlan1 Flags: RF F NS
CEF: Adjacency with MAC: 01005E010203D867D9BA4FE60800
Pkts: 0/0
(10.0.0.37,239.1.2.3) Flags: K DDE
SW Forwarding: 0/0/0/0, Other: 7/7/0
FastEthernet4 Flags: RF F NS
CEF: Adjacency with MAC: 01005E010203D867D9BA4FEA0800
Pkts: 0/0
Vlan1 Flags: RF F NS
CEF: Adjacency with MAC: 01005E010203D867D9BA4FE60800
Pkts: 0/0
Router A seems to send it okay (note the counts are off because I ran this a few minutes later):
rtr_a#show ip mfib 239.1.2.3 verbose
Entry Flags: C - Directly Connected, S - Signal, IA - Inherit A flag,
ET - Data Rate Exceeds Threshold, K - Keepalive
DDE - Data Driven Event, HW - Hardware Installed
I/O Item Flags: IC - Internal Copy, NP - Not platform switched,
NS - Negate Signalling, SP - Signal Present,
A - Accept, F - Forward, RA - MRIB Accept, RF - MRIB Forward
Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kbits per second
Other counts: Total/RPF failed/Other drops
I/O Item Counts: FS Pkt Count/PS Pkt Count
Default
(*,239.1.2.3) Flags: C K
SW Forwarding: 0/0/0/0, Other: 0/0/0
FastEthernet4 Flags: RF F NS
CEF: (process switching)
Pkts: 0/0
(10.0.0.37,239.1.2.3) Flags: K DDE
SW Forwarding: 5/0/64/0, Other: 0/0/0
Vlan1 Flags: RA A
FastEthernet4 Flags: RF F NS
CEF: (process switching)
Pkts: 0/5
Looking at the documentation online, it indicates that the router will translate the source address of the multicast packet. If that were the case, I would expect the source address in Router B to be 10.2.0.37, not 10.0.0.37.
Any help, tips or guidance would be appreciated.
Thank you.
