Wednesday, September 22, 2010

how to use your FRITZ!Box at home as a SIP registrar …

… in order

  • to call from outside and from wherever
  • through your FRITZ!Box
  • making use of all the advantages of the tariffs wired into the FRITZ!Box.
The recipe:
  • set your SIP client up as a local IP telephone!
  • make sure it works!
    (in case you're not at home,  and you cannot verify the local set-up,
    just double check, and maybe "ask someone, who knows"!)
  • telnet into you FRITZ!Box (of course inside the LAN)!
    a port-forward to an SSH server on your LAN is a good way to log-in to there and telnet to the FRITZ!Box on its LAN port
  • use nvi to edit /var/flash/voip.cfg (you can actually edit it any way you want):
    change the resp. entry – do you remember the "extension_number"?
    search for it resp. for this string!
  • make the change permanent using the utility voipcfgchanged,
    learn about permanently changing the configuration here!
    rebooting is not necessary!!!
  • now make your SIP client use the (WAN!!) IP address of your FRITZ!Box as SIP proxy
    (if you have a nice DNS name – of course: that will do it;
    keep in mind: DynDNS names sometimes fail to get properly updated;
    your "external" SIP registrar accounts might actually provide you with useful information like your IP address on their web pages, after your FRITZ!Box re-registered with the resp. account)
That's all.

No specific firmware necessary, a pretty young one will do, but you are on the bleeding edge anyway, I assume.

Enjoy!

1 comments:

Ysbrand Galama said...

yes, registering a SIP-client from outside works! I have a newer Fritzbox 7390, and there you have to edit /var/flash/voip.cfg. At the bottom of the file it has an entry like this:

} {
enabled = yes;
username = "$$$$2FEWPNwhateverQ3KNWHI3STDTPDXB6BIZ41gEZMSN
authname = "";
passwd = "$$$$A2VZKT1SJMLblablasometringEZMYSGNDNEBVSNFFZ6
clientid = "";
extension_number = 621;
reg_from_outside = no;
gsm_tethering = no;
tx_packetsize_in_ms = 0;
} {

and now all you need to do it change the "reg_from_outside = no" into a yes. Then reboot your Fritzbox and presto, works!