Hey list, So I'm using RIP outbound for my application which generally works fine for registrations. However, when sending INVITE requests, PJSIP doesn't advertise "Supported: outbound" in the request - though it does add ";ob" to the contact URI. Effectively this means that Kamailio doesn't detect the endpoint as outbound-supported (which is problematic of course). By default, Kamailio looks for ";ob" as a param in the first route-URI. If that's not found, it ensures "Supported: outbound" is present in the request and then checks for ";ob" in the contact param. Note it won't check the contact param if outbound support is not advertised. There are two workarounds here, which might reduce the severity of the bug (though it'd be nice to fix). The first is to force outbound support in Kamailio. This shouldn't likely cause problems for any clients, but also shouldn't be necessary. The second - and the workaround I chose to use - is to add ";ob" as a param to the proxy URI in the account configuration. This URI is copied directly into the first Route header for outgoing INVITE requests - which satisfies Kamailios requirement. Overall, however, I feel this should be advertised on the invite. Thoughts? Best, Colin