This may be outside the scope of this list, but maybe someone will incidentally have a suggesion.
Anyway, we use a Cisco SIP phone (I believe it is 7960). This works fine on our local network
with our SIP proxy program (we have our own so please don't ask who provides it ;-) we do).
I always set
Phone IP Address: X.X.X.Y
Subnet Mask
Sip number (in several places)
Sip proxy IP address: X.X.X.Z
Port (5060)
note that proxy and Phone IP address are on same network. As I say, this works fine.
NOW, we have a SIP proxy running on network A.B.C.D and our Sip Phone is on W.X.Y.Z
(completely different networks). In general we can get from W.X.Y network to A.B.C network
via ping, telnet, ssh, etc. However, we cannot seem to ping the SIP phone from other networks.
My guess is that while the SIP phone address is W.X.Y.Z, the router through which it goes may
have the address of W.X.Y.V (same network, different IP address) so to the external world
the SIP phone looks like it has the address W.X.Y.V rather than W.X.Y.Z, and so W.X.Y.Z cannot
be pinged (nor any other IP functions). But I can't set the SIP address to W.X.Y.V (actually I can but
that is the address of the router so it will be a conflict). I do set the SIP's gateway to W.X.Y.V but that
does not help. The SIP phone can be pinged locally but not from a different network.
i figure as long as I cannot ping the SIP phone from a different network, through the router, the SIP phone
will not be able to reach the proxy machine, A.B.C.D.
Any suggestions how I might make that IP address (W.X.Y.Z) available to the outside world?
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