MBG disconnecting calls after around one minute

[PC77375]

I am at the end of my rope here...Teleworker phones are intermittently dropping calls after around one minute. MBG version 7.1.21.0, MCD version 5.0 sp2 PR2.
Seeing the following in the event logs:

MBG  one-way audio  08:00:0F:47:D7:23  Major  Mon 21 Jan 2013 15:45:30 CST loss of rx stream from SS for 5008ms
MBG  one-way audio  08:00:0F:47:D7:23  Major  Mon 21 Jan 2013 15:43:32 CST loss of rx stream from SS for 5018ms
MBG  one-way audio  08:00:0F:31:74:D3  Major  Mon 21 Jan 2013 15:01:51 CST loss of rx stream from SS for 5017ms
MBG  one-way audio  08:00:0F:47:D7:23  Major  Mon 21 Jan 2013 14:38:27 CST loss of rx stream from SS for 5005ms
MBG  one-way audio  08:00:0F:31:74:D3  Major  Mon 21 Jan 2013 14:15:37 CST loss of rx stream from SS for 5005ms
MBG  one-way audio  08:00:0F:33:5D:9E  Major  Mon 21 Jan 2013 13:43:30 CST loss of rx stream from SS for 5015ms
MBG  one-way audio  08:00:0F:32:0B:53  Major  Mon 21 Jan 2013 13:34:35 CST loss of rx stream from SS for 5009ms
MBG  one-way audio  08:00:0F:31:74:D3  Major  Mon 21 Jan 2013 13:04:22 CST loss of rx stream from SS for 5007ms
MBG  one-way audio  08:00:0F:3F:F8:D5  Major  Mon 21 Jan 2013 12:55:01 CST loss of rx stream from SS for 5012ms
MBG  one-way audio  08:00:0F:3F:F8:D5  Major  Mon 21 Jan 2013 12:30:46 CST loss of rx stream from SS for 5016ms

Has anyone experienced this?
It seems to report as one-way audio, but on a few test calls there has been no audio in either direction.

[ralph]

Yes.  I've experienced it.
Firewall.

What firewall do you have?   Are you in DMZ mode?

Ralph

[acejavelin]

I have also seen this behavior, but caused by the router on the far-end, but still a firewall issue.

If this is happening on phones at just one site but other sites are fine, check the router on the far-end, depending on the model/configuration it might be as simple as just turning off SPI.

If multiple locations are effected, it is clearly something on the Teleworker end. Although I have gotten this to work in DMZ mode, clearly the most effective, efficient, and least troublesome is in in Gateway mode with one NIC directly on the public network.

[PC77375]

Found the issue. It was the firewall, a rule was missing so outbound packets were being dropped.

[ralph]

Did you beat your firewall admin?   

Ralph

[LoopyLou]

Pretty much every audio problem on teleworkers can be traced to programming in the firewall ( if the MBG is setup correctly ). Least that's my experience.