I do not think that this is a bad configuration. If the WRONG_IP_ADDRESS is the IP address of a gateway this would be a simple approach to bypass the billing logic in the SIP proxy to achieve free calls.

The INVITE is perfectly valid. For example, if a sip:[EMAIL PROTECTED] calls sip:[EMAIL PROTECTED] the Atlanta SIP proxy sees a similar request. (although usually the To URI would be the same as the RURI).

You could: screen the RURI for bad IP addresses (manually or by using the permission module).

regards
klaus

Andreas Sikkema wrote:
Klaus,

Maybe someone sent a SIP message with the local IP address in the R-URI to your proxy. According to your config this should not matter as you rewrite the domain for every incoming SIP request - except for loose-route.

The IP address in the Request-URI is one that for some reason (incorrect configuration?) is being sent by the SIP UA. This IP address is NOT the same machine as OpenSER...

The loose_route block could indeed be the culprit here. Is there a way I can see in an INVITE being sent to OpenSER that loose_route() will

return true?

This is the (sanitized) INVITE that is causing the problems:

INVITE sip:[EMAIL PROTECTED] SIP/2.0
Call-ID: [EMAIL PROTECTED]
From: <sip:[EMAIL PROTECTED]:[PROXYPORT]>;tag=45fa8
To: "[NUMBER]" <sip:[EMAIL PROTECTED]>;tag=as52bb63c2
CSeq: 101 INVITE
Via: SIP/2.0/UDP
10.1.2.71:5060;branch=z9hG4bK-45a33f186083645f5232ca79048af818
Contact: "[USERNAME]" <sip:[EMAIL PROTECTED]:5060>
Max-Forwards: 70
Route: <sip:[IPADDRESS_PROXY]:[PROXYPORT];lr>
User-Agent: [USER_AGENT]
Supported: timer
Content-Type: application/sdp
Content-Length: 151

(I've removed the body of the message; it's not very interesting here)

The problem is that the Request-URI contains [WRONG_IP_ADDRESS]. When
this OpenSER receives an INVITE it should never forward the INVITE to an IP address a SIP UA has added to the Request-URI. OpenSER should be the one

to decide this.

So far we've never had any issues in this area, so I don't want to
change too much in the config (like removing the whole loose_route() stuff) unless that is the only way I can solve this problem.

If the Request-URI would have been correct, [NUMBER] would have been rewritten to something usefull and the call would have succeeded.

For loose-route I would suggest to check for a to-tag too. Then, the called SIP UA should reject the call. You could also use dialog module to see if a dialog exists before forwarding in loose_route.

How would checking for a to_tag help? There is no existing Ddialog; this

is handling the initial INVITE message where it already goes wrong...


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