[NewBie] why I can't hear the voice of my co-worker

I already set up an SIP account for my co-worker in a different country using asterisk. When I call her, she can hear my voice. However, I can NOT hear what she says. I am really new to asterisks and phone system in general. So, I am not quite sure how to trouble-shoot the issue.

when I run “sip show peers”, I can see her account is shown.
Name/Username Host Dyn Nat ACL Port Status
822/822 222.127.. D N 44543 Unmonitored

Is it possible it’s because of my firewall? Also, what does “Port” refer to here? Is it the destination port that I should allow in my firewall?

It could be a firewall issue. Try port forwarding on UDP 5060, UDP 5061 and UDP 10000:20000.

thanks for your reply.

i am about to set the port forwarding as well. However, there is actually another person who is outside our network. She’s using a snom phone that communicates through 5060 port as well. We have no problem with her telephone. I assume if she’s fine with the current network configuration, then we don’t need to set the port forwarding. am I right?

SIP + NAT= big trouble. Not big as h323, but it is. May be try to switch on IAX2?
We cannot help this issue, until we don’t know your network topology.