On 18/06/2022 17:35, Anthony R. Gold wrote:
>> It's going to depend on the ITSP and whatever other means there are for
>> the Linksys to determine line is being called, but, if the ITSP will
>> support ports other than 5060, neither should be set to anything
>> remotely related to 5060, unless you like being called by toll
>> fraudsters at all hours.
> How do these toll fraudsters navigate the NAT that is almost certainly
> employed in the OP's router?
The same way as the ITSP does, for incoming calls.
Actually, if he's relying on dynamic NAT, the calls may not be being
sourced from 5060 anyway, although, in that case, various workarounds
will need to be in place, as SIP and SDP expect the port numbers used in
the requests to the ones to actually send to.
If this weren't a real problem, there would not be so much traffic about
using fail2ban with Asterisk.