Solved Incoming connections from 51.178.92.0/24 and others getting blacklisted

[Christian_B]

We're seeing incoming connections 51.178.92.132 and 51.178.92.133 like this:

2022/01/06 13:53:12.566|28220|0059|Inf|MYPHONE: 1ST Login User:XXXXXXXXX, Password:null, SessionID:b6d3d422-a556-799b-eb60-XXXXXXXXX, IP:51.178.92.132, ClientInfo:tcxmcu/11.0.0.29795, ClientVersion:1.0.0.0 2022/01/12 09:54:48.814|28220|0058|Err|MYPHONE: SessionId b6d3d422-a556-799b-eb60-XXXXXXXXX: DN with C2CID '' does not exist 2022/01/12 09:54:48.814|28220|0058|Err|MYPHONE: IP 51.178.92.133 is blacklisted

Also when I search the logs for 'DN with C2CID '' does not exist', there are many more occurences from other IP ranges which also seem to belong to 3CX servers.

Is this caused by conference links that were created with 3CX v16 and are no longer valid with 3CX v18?

 

[VasilisV_3CX]

Hi @Christian_B,

UPDATE

Yes, your initial assumption appears to be most plausible.

 

[LeonidasG_3CX]

Hi @Christian_B,

This is a known issue on V18. These can safely be ignored as they are the V16 MCUs attempting to reconcile lost data bursts for older meetings with your PBX. We've decided not to give this issue any attention as the old V16 infrastructure will be turned off in March as per https://www.3cx.com/blog/news/v16-web-meeting-eol/.

Old V16 MCUs getting blacklisted on V18 is inconsequential and can be ignored.

 

[Christian_B]

Ok, thanks for this information.