# \[help\] nat **URL:** \ **Category:** Asterisk Support\ **Created:** [November 25, 2005, 4:40pm UTC](https://community.asterisk.org/t/help-nat/2724 "2005-11-25T16:40:34Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![alexis.fecourt](https://avatars.discourse-cdn.com/v4/letter/a/ee59a6/32.png) [@alexis.fecourt](https://community.asterisk.org/u/alexis.fecourt)\ **Post date:** [November 25, 2005, 4:40pm UTC](https://community.asterisk.org/t/help-nat/2724/1 "2005-11-25T16:40:34Z")
Hi 😄, I have a NAT problem… That is the network configuration (the Asterisk server has 2 intefaces) : ![](http://berryballade.free.fr/perso/NAT-pb.png) \*\*\*\*\* sip.conf \*\*\*\*\* [general] context=default language=us insecure=invite auth=plaintext bindport=5060 bindaddr=0.0.0.0 allow=ilbc srvlookup=yes externip=172.17.70.247 localnet=10.0.0.0/255.0.0.0 nat=yes register =\> [0141877002@172.17.69.107](mailto:0141877002@172.17.69.107)/7002 [7002] type=friend callerid=“SJphone” \<7002\> context=local host=dynamic disallow=all allow=gsm allow=ulaw allow=alaw allow=ilbc allow=speex * * * \*\*\*\* extensions.conf \*\*\*\* [general] static=yes writeprotect=no autofallthrough=yes clearglobalvars=no priorityjumping=no insecure=invite [globals] [default] include =\> local [local] exten =\> 7002,1,Dial(SIP/7002,10,tT) exten =\> 0675464598,1,Dial(SIP/0675464598@172.17.68.107) * * * Now I try to call the intern phone (7002) from the outside (0675464598), I capture the frame with ethereal, every thing is ok : ![](http://berryballade.free.fr/perso/out-in-sip.png) ![](http://berryballade.free.fr/perso/out-in-rtp.png) But if I call the outside from the inside ! ![](http://berryballade.free.fr/perso/in-out-sip.png) ![](http://berryballade.free.fr/perso/in-out-rtp.png) There is clearly a problem with an additional SIP INVITE send by Asterisk which contains a bad SDP: Asterisk says to communicate directly ! Frame 14 (816 bytes on wire, 816 bytes captured) Internet Protocol, Src: 172.17.70.247 (172.17.70.247), Dst: 172.17.69.107 (172.17.69.107) User Datagram Protocol, Src Port: 5060 (5060), Dst Port: 5060 (5060) Session Initiation Protocol Request-Line: INVITE sip:0675464598@172.17.69.107:5060 SIP/2.0 Message body Session Description Protocol Connection Information ©: IN IP4 10.51.51.52 Frame 16 (751 bytes on wire, 751 bytes captured) Internet Protocol, Src: 10.51.51.51 (10.51.51.51), Dst: 10.51.51.52 (10.51.51.52) User Datagram Protocol, Src Port: 5060 (5060), Dst Port: 5060 (5060) Session Initiation Protocol Request-Line: INVITE sip:7002@10.51.51.52:5060 SIP/2.0 Message body Session Description Protocol Connection Information ©: IN IP4 172.17.68.254 It should not send the direct IP of the phones ! I solved the problem by forcing the use of different codec: the internal phone uses GSM and the external one uses iLBC. With that configuration Asterisk does his proxy job. But I am looking for a better solution. Please help me. Alexis. ---
**Author:** ![greyhound](https://avatars.discourse-cdn.com/v4/letter/g/e47774/32.png) [@greyhound](https://community.asterisk.org/u/greyhound)\ **Post date:** [November 25, 2005, 5:25pm UTC](https://community.asterisk.org/t/help-nat/2724/2 "2005-11-25T17:25:36Z")
Sorry I can’t help. Still a little wet behind the ears. But I wanted to comment and ask a question: Comment: slick diagram of the network! Question: does ethereal produce those communication graphs automatically? If not, how did you produce them? Last time I used ethereal, a few years ago, I don’t recall seeing anything like that. It’s quite a nice way to visualize the exchange! Thanks. john ---
**Author:** ![rightbrain](https://sea1.discourse-cdn.com/asterisk/user_avatar/community.asterisk.org/rightbrain/32/511_2.png) [@rightbrain](https://community.asterisk.org/u/rightbrain)\ **Post date:** [November 25, 2005, 6:19pm UTC](https://community.asterisk.org/t/help-nat/2724/3 "2005-11-25T18:19:49Z")
Have you tried “canreinvite=no” yet? ---
**Author:** ![netjunkie](https://avatars.discourse-cdn.com/v4/letter/n/f0a364/32.png) [@netjunkie](https://community.asterisk.org/u/netjunkie)\ **Post date:** [November 26, 2005, 6:50pm UTC](https://community.asterisk.org/t/help-nat/2724/4 "2005-11-26T18:50:58Z")
There is an amazing tool called siproxy and can be found on sourceforge. It is robust, feature rich and gets the job done. We have it running on a cluster and allows us to present 10 cluster nodes to our clients as a “single asterisk box”. can do both in/outbound proxying. ---
**Author:** ![alexis.fecourt](https://avatars.discourse-cdn.com/v4/letter/a/ee59a6/32.png) [@alexis.fecourt](https://community.asterisk.org/u/alexis.fecourt)\ **Post date:** [November 28, 2005, 8:31am UTC](https://community.asterisk.org/t/help-nat/2724/5 "2005-11-28T08:31:46Z")
Hi, I use Ethereal Version 0.10.13, and I do the graphs with it : Statistics/Flow Graph… I will search about canreinvite. Thanks. Alexis. ---
**Author:** ![alexis.fecourt](https://avatars.discourse-cdn.com/v4/letter/a/ee59a6/32.png) [@alexis.fecourt](https://community.asterisk.org/u/alexis.fecourt)\ **Post date:** [November 28, 2005, 8:54am UTC](https://community.asterisk.org/t/help-nat/2724/6 "2005-11-28T08:54:32Z")
canreinvite=no is the solution.