3Com BETA Getting Started Manual - Remote Sip Connectivity
Chapter 5. SIP Configuration
When you select this, the Telecommuting Module makes no checks of incoming SIP URIs.
It becomes possible in theory to trick the Telecommuting Module to send SIP packets any-
where, so security is drastically reduced.
Keep username in URIs
will make the Telecommuting Module keep the original username
pare of the Contact URI, and only replace the domain part.
When you select this, it will be impossible for the remote SIP server to tell if requests
for a certain user belong to one or several clients, as it has no means of telling the client
registrations for a user apart. This means that if a user registers from two clients, and then
unregisters from one of them, the SIP server will remove its only registration record for that
user.
The Telecommuting Module also makes no checks of incoming SIP URIs. It becomes possi-
ble in theory to trick the Telecommuting Module to send SIP packets anywhere, so security
is drastically reduced.
Remote SIP Connectivity
Remote NAT Traversal
If your SIP client is not STUN-capable, you can use the built-in Remote NAT traversal fea-
ture of the Telecommuting Module. The client must register on the Telecommuting Module
(or through it).
The SIP client needs to re-REGISTER, or respond to OPTIONS packets, rather often for this
to work. The exact period for this depends on the NAT-ing device, but 20 seconds should be
enough to get across most NAT boxes.
Remote NAT traversal
Switch this function on or off.
Remote Clients Signaling Forwarding
Many SIP servers need to separate signaling to and from remote clients from signaling to
and from the SIP Trunk. For this purpose, you can specify which IP address and port the
remote clients will connect to. This can’t be the same IP address and port as what the SIP
provider uses!
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