Minimum UDP port requirements

Posts: 3 · Posted: Tue Jun 13, 2006 9:03 pm Post subject: Minimum UDP port requirements

I have my Linksys PAP2 Voip device attached to my internet connection through a Cisco 2621 router and Catalyst switch. The Vonage Linksys device user manual calls for forwarding UDP port 10000-20000 amongst others. As far as Cisco hardware goes, you can forward a port range with a single statement in the config on a PIX firewall but not on a standard router like mine. It would be impractical if not impossible for me to create 10k individual port forwarding entries in my router's NAT table.

What are the minimum port forwarding requirements for Vonage to work properly? It seems impossible to get an answer from Vonage about this and their tech support hold times are just out of control. Thanks.

Posts: 35 · Posted: Tue Jun 13, 2006 9:20 pm Post subject:

the ports are configurable through provisioning, but you'd have to contact Vonage to get them to change the port range on the devices, by default the udp ports for the audio stream are 10050 to 10150 and 5061 or 10000 on udp for the sip traffic. You can also forward 2400 for tftp for the device or 69 if you prefer to use the standard tftp port.

Posts: 476 · Posted: Tue Jun 13, 2006 9:27 pm Post subject: Re: Minimum UDP port requirements

fabian21 wrote:

What are the minimum port forwarding requirements for Vonage to work properly? It seems impossible to get an answer from Vonage about this and their tech support hold times are just out of control. Thanks.

Technically you shouldn't have to forward any ports if you're using a NAT firewall. Since the adapter makes the connection to the Vonage server to register NAT will handle all the resulting inbound connections.

Posts: 3 · Posted: Tue Jun 13, 2006 9:33 pm Post subject: Re: Minimum UDP port requirements

blakadher wrote:

fabian21 wrote:

What are the minimum port forwarding requirements for Vonage to work properly? It seems impossible to get an answer from Vonage about this and their tech support hold times are just out of control. Thanks.

Technically you shouldn't have to forward any ports if you're using a NAT firewall. Since the adapter makes the connection to the Vonage server to register NAT will handle all the resulting inbound connections.

Ok, but, does the phone adapter keep its connections to Vonage open at all times? I can check my router's NAT table but would it do that? If not, then NAT won't be able to translate the inbound connections from Vonage w/o static port entries.

Posts: 35 · Posted: Tue Jun 13, 2006 9:38 pm Post subject:

if you fire up a packet sniffer, you can see the Vonage device register every 20 seconds with the Vonage proxy. This is done for a reason, it keeps the nat tables populated with the port forwarding to allow unsolicited incoming traffic (inbound call for instance) on those ports without needing to forward those ports specifically. If one of those registers misses for some reason though (it is udp after all), port forwarding will act as a backup

Posts: 3 · Posted: Tue Jun 13, 2006 9:40 pm Post subject:

vidmaster wrote:

if you fire up a packet sniffer, you can see the Vonage device register every 20 seconds with the Vonage proxy. This is done for a reason, it keeps the nat tables populated with the port forwarding to allow unsolicited incoming traffic (inbound call for instance) on those ports without needing to forward those ports specifically. If one of those registers misses for some reason though (it is udp after all), port forwarding will act as a backup

Excellent. Thank you all for your help.