[asterisk-users] SIP attacks

[Thomas Kenyon]

I have been receiving a lot of hack attempts today (home and work) 
multiple SIP registration requests (none of them managed to find a 
relevant username before fail2ban kicked in).

Is this happening to a lot of people now?

I only have SIP available externally for enum purposes, is it possible 
on a host which is specified as dynamic to choose a valid hostmask in 
sip.conf on a per peer/user basis?

TIA for any response to this.