SIP Trunk through ASA to Internal Phone Server?

[JB-TX]

Hello All,

A am a bit new to SIP trunks with the ASA. I wanted to see if someone could give me a best practice review? Using a Cisco ASA5510 version 8.4(5) and we have an internal Mitel Phone server. SIP trunk is being handed off by Comcast.

These are my assumptions?

1 to 1 NAT to phone server with TCP & UDP ports forwarded.

SIP Inspection on or off? I've seen mixed results of information.

Phone server and phones on it's own isolated VLAN.

Thank you in advance.

[balaji.bandi]

here is my comments :

1 to 1 NAT to phone server with TCP & UDP ports forwarded.

BB - 1 to 1 NAT between you and SIP provider Public IP to Private IP  - required ports for SIP trunking, allowed ACL in place.

SIP Inspection on or off? I've seen mixed results of information.

Inspection Off.

Phone server and phones on it's own isolated VLAN.

BB -yes, i believe you have voice and data VLAN in place with DHCP, you need DHCP option for Phone to register.