VoIP problems

[ciatnetwork]

Hi

We have a E1 on Cisco3640 and router WAN Cisc3640 doing NAT. The VoIP in this scenario works fine, but after, we change the router WAN to Cisco 7604 but now we get voice in one-way. We're checking the E1 and there is not problem. What should we check?? Many thanks.

[paolo bevilacqua]

You should check respective IOS versions and configuration.

[ciatnetwork]

If we move E1 to DMZ network it works even using cisco 7604.

[paolo bevilacqua]

May be a difference due to some NAT behavior or bugs in different version. Without more details, is impossible to tell.

[leungcm]

check ACL both sides

[ciatnetwork]

I remove them but the problem is still there.

Thanks