Qwest / Centurylink DSL Web site timeouts, hangups, or failures while running a firewall or router with static IP addresses.
Recently I setup the Qwest DSL service in my home. It worked great, but after a couple days I started to get hang ups and timeouts or hangups while browsing the web. Speed tests still showed the correct speeds and rebooting all my hardware didn’t solve the issue.
I run PFSense as my internet firewall. (check it out, http://pfsense.org ) I love PFSense, it gives me very fine grained control over just about everything, even simple traffic speed limiters for certain parts of my LAN. (like my kid’s systems, I don’t want them eating my my bandwidth with Youtube!) In the past, I’ve had some issues with my client networks and firewalls while using Qwest DSL and PFSense. I found almost ZERO help on Google searches, which I find surprising, because I can’t be the only one with this setup. But, to get to the point, you need to setup the Qwest modem advanced options to use Dynamic Routing. I use version 2.
If I plug in and connect directly, I do not get the connectivity issues, so I knew something with the PFSense was, to put it mildly, not being cooperative. Setting to Dynamic Routing fixed this issue on 3 client networks AND on my recent install at home.
Note, too, that all these networks have static IP’s or static blocks. I tried setting to use transparent bridging, which didn’t help. But one time I setup PPPoE directly on PFSense, and that did help. In the end, the only way I could reliably run PFSense on Qwest DSL was to disable NAT on the modem, setup Dynamic Routing, and purchase static IP address(s). Keep in mind, you need to use the “Static IP” setup from Qwest and NOT run transparent bridging, like I assumed. Read their docs, there’s a special setup for this in the Quick Setup section of their modem firmware.
Also, I had this issue on most of the later model modems and firmware, but NOT on the oldest Actiontek modems running old firmware. (like the 701’s) But on the newer Qwest firmware (with the blue background and preschool-style-coloring :) I had to enable Dynamic Routing. Also, I have the newer Zyxel Q1000Z modem now, same issue.
I have no understanding of why this happens. It doesn’t make any sense to me. Although, just to throw an idea out there, maybe it has to do with the way the modems manage hops from the external destinations.  From what I read, dynamic routing has something to do with maintaining the hops between routers online.  Maybe, since using the modem with static IP’s basically sets it into bridging mode, it incorrectly maintains that hop information, or at the very least it doesn’t identify itself correctly.  So what may happen is some routers out there get flaky and don’t respond well with your bridged modem by the time they communicate with your firewall.  Some do fine though, which would explain why some sites fail and some don’t.  I don’t believe PFSense is doing any dynamic routing protocol work, at all.  It’s just firewalling my LAN, right?  So all I can assume is, since the Qwest modem is in between me and the rest of the internet, IT has something to do with that communication breakdown using the dynamic routing.  Of course, I really don’t know what I am talking about and making complete assumptions!  But hey, its just an idea. Maybe someone who know’s more than I do can shed some light on it. :)