Natting multicast problem...

Is it possible to find out the specific version of code on the San Jose lab
routers? Are they all running the same code? Would this be a violation of
NDA to share? The reason I'm asking is I think I'm running into a NAT bug in
12.4(23). At least I think it's a nat bug...

R7 s0/0/0 (150.100.78.7/24)--------------R8 s0/0/0 (150.100.78.8/24)

Running RIP between the routers, the requirement is to not send multicasts or
broadcasts across the link and you can't use "neighbor" w/passive interface.
Here's the related parts of the NAT config:

int s0/0/0
ip nat outside

access-list 101 permit udp host 150.100.78.8 eq 520 host 224.0.0.9 eq 520

ip nat pool rip 224.0.0.9 224.0.0.9 netmask 255.255.255.0
ip nat outside source list 101 pool rip

Here's what debug ip nat detail shows:

Aug 20 01:51:57.291: NAT: failed to allocate address for 150.100.78.8,
list/map 101
*Aug 20 01:51:57.291: NAT: failed to allocate address for 150.100.78.8,
list/map 101
*Aug 20 02:02:39.599: NAT: translation failed (B), dropping packet
s=150.100.78.8 d=224.0.0.9

I thought it might have had to do with the pool referencing multicast space or
something like that so I tried a different pool with a random unicast IP and
got the same "failed to allocate..." error.

I found this bug, but it only refers to this being a problem when natting at a
GRE tunnel (Bug ID CSCsy97506
<http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fet
chBugDetails&bugId=CSCsy97506&from=summary> ) so I tried disabling ip cef and
ip mroute cache on the interface, but that didn't make any difference. I also
tried a static translation:

ip nat outside source static udp 150.100.78.8 520 224.0.0.9 520

That didn't work either, but I didn't see any errors show up in my "debug ip
nat detail"... I see the translation:

Pro Inside global Inside local Outside local Outside global
udp --- --- 224.0.0.9:520 150.100.78.8:520

but it's not getting used:

*Aug 20 02:05:49.123: IP: s=150.100.78.8 (Serial0/0/0), d=224.0.0.9, len 92,
rcvd 2
*Aug 20 02:05:49.123: UDP src=520, dst=520
*Aug 20 02:05:59.155: IP: s=150.100.78.7 (local), d=224.0.0.9 (Serial0/0/0),
len 412, sending broad/multicast
*Aug 20 02:05:59.155: UDP src=520, dst=520

Any ideas? Is my config jacked?

Thanks,

Ron Johns
Sr. Network Engineer
IT Department
CCNP, CCDP, CCSP, CISSP
AT&T WiFi Services

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Received on Wed Aug 19 2009 - 21:15:27 ART