[geeks] VOIP phone with inside/outside network

[der Mouse]

> Polycom 330's don't do well through NAT,

$DAYJOB actually has hundreds of Polycoms, over a dozen of them 330s,
in service right now.  Most of them are behind NAT.

> I could be wrong however the last time I checked Polycom's
> knowledgebase they basically said that the firmware can't do
> effective NAT.

This is true, in that the phones are not NAT-aware.  But if the NAT is
done right, they don't need to be.  But, in particular, this means that
either you need to have a wired-down mapping (and thus effectively an
infinite state timeout) or a NAT state timeout long enough that
periodic reregistration and/or qualification (if done) keeps the
mapping alive.  What Polycoms don't do is push NAT knowledge to the
endpoint (the phone), such as by doing STUN.  (In my perhaps
iconoclastic opinion this is correct; if NAT breaks something, the
right thing to do is to get rid of the NAT.  It breaks the assumptions
underlying IP, and it's a tribute to the robustness of IP and the
protocols built on it that as much works through NAT as does.)

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