Showing results for 
Search instead for 
Did you mean: 

AMA-CUCM Troubleshooting: Best Practices for Reading Trace Files

One way Communication issue since changed IP addressing on voice vlans


We have changed IP addressing of our VoIP phones from Public Range to Private 10.x.x.x. Our Main Site IP addresses change took place before I started so don't know if some configuration change was made on CUCM 6.1.3 to make it work. I changed the IP addressing of Voip Phones on one of the Remote site connected to main site (where Publisher / Subscriber resides). At the remote site I enabled the DHCP scope to allocate IP addresses to IP phones. I created the voice vlan and configured the correct voice vlan to switchport IP phone is connected. Phone gets the IP from DHCP scope and also gets correct parameters such as gateway,option 150 etc. Phone gets registered to Subscriber call manager. I have checked the IP cache and I see the session to port 2000.When

I call from our main site to phone assigned to new VLAN ,Remote site phone can hear us but we can't hear them and issue remains the same when call is initiated from remote site to phone's on other VLAN's or sites.

At remote site I installed another phone and assisgned the switchport to new voice vlan then both new phones can communicate to each other but same issue in communication to phones on other vlans / locations

I have checked all the access-lists and FWSM but couldn't see any issues ....ANY IDEA what's causing one way communication issue cos previous team changed the IP addresses on our main site but no such one way communication issue. Interesting thing is that I picked one of the free subnet from Main site IP address planning structure and implemented at remote site and had no issues with communication at all

Cisco Employee

Thank you for your posting and interest in the Cisco Support Community.  For best practices on posting documents in this community you can refer to

For technical questions related to a Cisco Product or Technology, we encourage you to post on the Cisco Support Community NetPro Discussions. For your specific issue, you can go to IP Telephony discussions forum.

CreatePlease to create content
Content for Community-Ad
August's Community Spotlight Awards