SIP peer on a different subnet from the server is UNREACHABLE (asterisk -r -> sip show peers), even though it can be pinged and port 5060 is open, it could be because the subnet is not listed as a ‘localnet’ in sip_general_custom.conf.
Peers have also become unreachable when moving an extension to a different piece of hardware while a SIP Proxy is running (ie. Endian Firwewall). Restarting the proxy may help.
