Asterisk SIP Extentions from one IP

Hi All
I am ne to asterisk and having following problem
I am running 1.2 asterisk . wih NAT

I have 4 remotesip extentions for inbound from some ohter company .

three were working find once I added the fourth one the 3rd one stop working and if I disable 4th 3rd on again starts working .

I have register in sip conf
register:3rd:secret@domainIP/3rd
register:4th:secret@domainIP/4th

just to let you know that the domain ip is the same

after that I created in sip
[3rd]
nat=yes
dtmfmode=rfcxxxxx

and so on
same for the 4th
the extention conf

simple sending call to one queue
same for 4th

but only one works at one time
is there any problem with one IP for both or one port for both and any other issue Please Please reply Please I am stuck and going to losse my job Please help

If you are new to Asterisk, please do not use version 1.2. It hasn’t been supported for some time now.

Just blogged about this, perhaps this will help:

blog.bitwaretech.com/2009/08/how … erisk.html