Match conditions for a trunk rule. All non-None fields must match (AND).
from matches the SIP From header (caller), to matches the SIP To header
and Request-URI (callee) of the outgoing INVITE/REFER.
Rewrites the user and/or host of a SIP URI. When a host value carries no
port (e.g. "172.25.225.2"), the original URI port is preserved; include a
port (e.g. "172.25.225.2:15060") to also change it.