We have an AT&T DSL Modem with 5 public IPs (let's just use 18.104.22.168 to 5), a SonicWall TZ 170 and several physical servers on a gigabit switch. The SonicWall is the only device plugged into the DSL Modem with a WAN Port Address of 22.214.171.124. Our domain has an A record for www to 126.96.36.199 (Web), mail to 188.8.131.52 (OWA/OA) and smtp to 184.108.40.206 (Mail Gateway) and everything is working.
So how does incoming traffic -- other than 220.127.116.11 -- get to the individual servers on the internal, NATted LAN (192.168.0.1/24) if the SonicWall's WAN Port address is 18.104.22.168? I don't see any Access Rules specifying any of the other public IPs but I do see respective Ports being forward to the appropriate, physical server on the LAN side. I accessed the Netopia DSL Modem's configuration but don't see any configuration settings that's doing it.