Different setup - 503 error

My setup.

Asterisk@Home v1.4, in the DMZ of router.

X-lite phone on local lan with asterisk server, distant end X-lite phone on different network behind NAT firewall.

I can log in on the Asterisk server from the distant end, but when I dial an internal number (say *200) or *43 for echo test, i get the “503: Service Not Available error”

in the sip.conf i have nat=yes, and have set the externip and localnet ip’s.

for the distant phone i have nat=yes set in the extension settings. I have ulaw, glaw, and gsm allowed for the distant phone.

where else can i look to get this corrected?

Thanks in advance,


Have you set the NAT firewall up to forward the relevant ports properly? It won’t work unless you do.

Thanks for the reply…

The Asterisk is in the DMZ on the firewall…

but i might have it figure out…one of the options in the extension set up is the context field…I am not sure how or what this field is supposed to do, but if set to “from-sip-external” the i get the 503…I have reset it to “from-internal” and currently awaiting a friend to log in on a new extension i created for him and see if it will work then…

where can one get a listing of all the options for the various fields?..i have only been able to get bits and pieces here and there, and would like something a little more definitive…


Do you mean there’s no firewall/NAT between the server and the phone? If so, then you need to have nat=no , not nat=yes - at least in the stanza for that particular phone.

voip-info.org/tiki-index.php … nfig+files

Hi Will,

No…the server is in the DMZ on my local network…the softphone i am trying to call in with in behind firewall on a totally different network…

Thanks for the link…will check it out…


i think u’d better make a nat on your router too