These can be a real hurdle when setting up VoIP, help others by posting your configs, tips and tricks or simply ask others for help if you're stuck.
User avatar
By Ian_Dob
Posts Avatar Topics
Hi guys,

I wonder if you could help me, I've been asked by an interviewer to do some research on UDP. Apparently their is a vendor advising that you can block all inbound UDP ports on their firewall and still operate a SIP/VoIP cloud based system through it. I've had a look online and cant see any vendors listing this as a feature. I've asked a colleague who mentioned that Palo Alto networks has mentioned having something like this feature, but again after having a good look around their website I have drawn a blank.

As far as I'm aware unless their is a UDP session already established the UDP ports would have to be open to accept incoming calls, if the source server cant establish the session through UDP then the call will fail. Part of me is wondering if this is a trick question.

Thanks in advance for any help.
User avatar
By WelshPaul
Posts Signature Likes Avatar Topics
Not something I have tested or tried myself but blocking listening ports on a firewall will not stop VoIP communications I believe. Did a little searching on google and found this: ... ng-or-voip

Will have to put this on my to-do list!
Cisco 8841 3PCC

Before we go any further... Can you verify that the d…

VIP Membership

Good stuff, I see it now. Thanks @WelshPaul !

You can register multiple devices against the same SI…

I'm sure this is a config problem as it affects 3 off S…

Sign up for VIP membership