[Serusers] Ser running behind a NAT

Nils Ohlmeier nils at iptel.org
Tue Jul 15 16:56:29 CEST 2003

On Tuesday 15 July 2003 11:00, George KAPELIOS wrote:
> Is anyone able to answer if SER could run without
> problems behind a NAT ?

Running a server behind NAT is always a bad idea!
(Except you just want to serve the clients behind the NAT.)

> In our test, the server is assigned with a private IP
> address and port 5060/udp is open on the NAT router.
> UAs are alway able to register through public IP
> addresses, but sometimes there are call setup problems
> (for example a UA is keep trying to call a registered
> user until timeout, or at the receiver end a new call
> rings for once or twice and then call is terminated
> for "unknown reason").

Are your UAs only on the public side?
Do you use Record-Routing?
How do you make SER aware of its public IP? (Does your public IP change 
etc. ...
Please follow http://www.iptel.org/ser/bugs/ on problem reports. In this case 
a network dump could enlight us... and could increase your probability for an 

> Is any other port or range required to be open in the
> NAT?


> Any knowledge or suggestions?

Suggestion: forget your server behind NAT.
If you want to set up a server behind the NAT to connect the users from behind 
the NAT with the Internet, then please search the mailing list archives. This 
solution includes many problems, and solutions depend on the used UAs and 
mayn other factors.


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