A local Asterisk server for just a few SIP devices is overkill in my
opinion, unless you have lots of SIP devices to connect.
My workaround is running siproxd on my M0n0wall box and configure my SIP
devices or programs to use
my M0n0 as an Outbound proxy.
This fixed some other problems with my SIP devices, since a STUN server
configuration in SIP does not work
well with M0n0.