Firewall problem with dropped calls

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AlanR
Posts: 2
Joined: Wed Dec 03, 2008 5:12 pm

Firewall problem with dropped calls

Post by AlanR » Wed Dec 03, 2008 5:23 pm

I have a problem with a firewall set up in a cable modem/router - Motorola SBG900. I have set up the ports from the ooma knowledge-base article: UDP 1194, UDP 3480, UDP 514, UDP 49000-50000 and TCP 443. Several calls I made have been dropped after a few seconds. If I disable my firewall, this does not happen, but I'd rather not do that. Does ooma use any other ports that need to be set up?

The router has a browser interface used to set up. I can either set the firewall policy to high/med/low risk or I can customize it. The high/med/low policies use packet filtering to block disallowed inbound traffic. My current setting is customized - for that I define a list of ports manually. It allows me to specify a port range, protocol, allow outbound, allow inbound and protocol# (don't know what that is but it is set to 0). I added the ooma ports to this list in my customized settings.

Both the router and the ooma hub run DCHP - I don't know if that's ideal?

I tried e-mailing and calling support on the phone this morning but spent half an hour on hold and gave up.

I tried plugging the phone into the hub instead of the scout and have the same problem - when I turned on my firewall and made a call, the call went through but then cut off after a few seconds.

Anyone seen this or have any ideas?

Thanks,

Alan

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Dennis P
Ooma Moderator
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Joined: Fri Apr 25, 2008 9:09 am
Location: Palo Alto, CA
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Re: Firewall problem with dropped calls

Post by Dennis P » Thu Dec 04, 2008 12:25 pm

Is there a way to turn off Denial of Service attack prevention? I've seen firewalls interpret VoIP traffic as a DoS attack and stop forwarding the traffic after a few seconds.

You could also try setting up ooma on the firewall's DMZ.

AlanR
Posts: 2
Joined: Wed Dec 03, 2008 5:12 pm

Re: Firewall problem with dropped calls

Post by AlanR » Fri Dec 05, 2008 11:28 am

I don't have a way to turn off denial of servie attacks.

I tried setting ooma in the firewall's DMZ and this works - no dropped calls. However, since my network and computers are all downstream of ooma won't this put my whole network in the DMZ?

Thanks for your help!

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