Appendix A. More About SIP
The Telecommuting Module always rewrites the Contact when a SIP request is forwarded through. To prevent this rewriting, the URI Encoding and Preserve Username For All Requests settings can be used.
Via
The Via header is used to keep track of which route the SIP request was sent. The response is sent back the same route.
The Via header is always rewritten by the Telecommuting Module when the SIP signaling crosses a NAT border (when the IP addresses change).
The Telecommuting Module can remove Via headers, when the server receiving the SIP request will not accept requests with more than one Via header. This is done using the Remove Via Headers setting.
The
The
You can force the Telecommuting Module to add
Route
The Route header is used to send SIP signaling via a predefined route. All
The Route header is always rewritten by the Telecommuting Module when the SIP signaling crosses a NAT border (when the IP addresses change).
The
Some content types are automatically allowed through the Telecommuting Module, but most types must be allowed by configuration. For this, the Content Types table is used.
If a SIP packet is not allowed because of the content type, this error message is shown in the log: SIP unaccepted content - deny.
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