Are these ingress gateways or combo gateways ingress+vxml ?
Off the top of my head an ingress gateway needs :
1. 5060 SIP
2. RTP media ports
3. SSH / Telnet for OAMP depending on how you set it up
A VXML gateway needs the same ports and additionally :
1. 8000 for Call Server
2. 7000 for VXML Server if you use it
3. 80 for the mediaserver (IIS)
And unless you use i.e. ASR/TTS or other exotic setups, that should be about it I reckon.
Cheers,
Kris