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| reply to jeffpulver
Re: [FWD] Is BT's DSL Service Blocking UDP Port 50 I am surprise no one has replied, the reason is probably that BT territory runs 6 hours ahead of Eastern Time.
What I can tell from Mexico is that Telmex has apparently begun putting some DSL services behind some sort of firewall. You can access the internet just fine, but you can not run any server or services from these DSL lines.
FWD on these lines will work only if you enable SIP proxy, this is required even when you get a public IP address, and even if you do not run behind NAT, as this is the only way to open ports on the firewall.
I have two offices that were linked with VoIP using H.323 and Cisco 1700 routers. They ran fine until Telmex fire-walled their DSL. Now I am trying to figure out if I can configure SIP on the Cisco 1700 routers and make them work using the FWD SIP proxy.
Telmex says that if we can access the internet from the DSL, then the DSL is working fine. That their low end DSL service is not meant to run services from the user side. Of course they offer that if we want to make a VPN, or P2P VoIP work, we can pay Telmex and extra $100 per month per DSL and get a fixed IP address that is not fire-walled.
I guess Telmex can still teach BT a few dirty tricks | |
 roamer1sticking it out at you
join:2001-03-24
Atlanta, GA | said by know2much:I am surprise no one has replied, the reason is probably that BT territory runs 6 hours ahead of Eastern Time. What I can tell from Mexico is that Telmex has apparently begun putting some DSL services behind some sort of firewall. You can access the internet just fine, but you can not run any server or services from these DSL lines. FWD on these lines will work only if you enable SIP proxy, this is required even when you get a public IP address, and even if you do not run behind NAT, as this is the only way to open ports on the firewall. Blocking ALL inbound ports is rather strange...usually it's just ports likely to be abused by hackers or servers.  Of course, most "regular" VoIP services (Vonage, etc.) use SIP proxies by default to reduce support issues and because the bulk of the traffic is to the PSTN (so there's no real advantage network-wise to using STUN), so what Telmex is doing isn't really going to reduce VoIP traffic.
I know of a few US ISPs that stick customers behind NAT, including one municipal broadband provider in the Atlanta area and one major wireless phone carrier, but they're relatively few and far between, and most give customers the option of a public IP for free or at nominal cost.
-SC
--
"it seems like all you ever buy is Abercrombie and cell phones" --a friend
No-Bull SE US Wireless Info: »www.sewireless.info/
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