Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

nat translation failed

Hi everyone,

I have SCCP phone (7940) which behind 851W and have usually "translation failed" erros if I debug ip nat, which cause some packets to drop.

I've tested before with 7911 and don't have such issues which cause phone to unregister because of packet drops.

Any ideas what could be wrong?


Re: nat translation failed

The following are bugs related to your issue.



New Member

Re: nat translation failed

These seems to be very old bugs and fixed long time ago. That's probably something new i suppose.

Hall of Fame Super Gold

Re: nat translation failed

Don't bother, for some reason people from that firm like mentioning bugs at random.

Now, can't you just set a gre tunnel between 851 and cme, and so forget all and any NAT issue ?

New Member

Re: nat translation failed

I've already running ipsec tunnel but I have to changes source address of packets. But this force me to make another tunnel from 1801 (which working fine behind nat) only for phones.

This increase latency and jitter (ip telephony forbidden in UAE) ISP adds jitter and latency in most encrypted connections.

It's seems I have no choice but make another tunnel or upgrade 851 to 871 with advanced ip services.