Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
New Member

Cisco SX20 with ISDN Link : Receving calls from an unknown/strange numbers

Dear Readers and Guru's,

 

We are using a Cisco SX20 with ISDN Link due to some our regional offices still using ISDN connection, anyways, this is working fine. The only problem I am experiencing is the fact there are a lot of unknown established calls, examples below ;

1003, 3500, 100, 7070, 1003 and etc..

 

the format of the incoming call will start with an unknown number and followed by our SIP number ; 1003@***.**.*.***:5060

I want to permanently block this unknown callers as this is so annoying during our Video Conferencing meeting it keeps on ringing on the screen..

 

I was told that it has something to do with the network/firewall settings but honestly i don't know where to start.

i had attached a screenshot of the unknown numbers we are receiving.

 

TIA guys.

2 REPLIES
Hall of Fame Super Gold

Duplicate post.  Go here:

Duplicate post. 

 

Go here:  https://supportforums.cisco.com/discussion/12217626/cisco-sx20-receiving-incoming-calls-unknown-sources

Cisco Employee

Hi, In codec , can you try

Hi,

 

In codec , can you try the following config. change and check if the unknown calls are stopped ?

system configuration -> SIP -> ListenPort -> Off

Thanks,

Deva G

 

114
Views
0
Helpful
2
Replies
CreatePlease to create content