I'm having a very strange problem with a Fedora Core 5 (FC5) box I set up recently as a MythTV frontend: almost all outgoing TCP connections stall after transferring some data (sometimes just a few kilobytes, sometimes after several megabytes)! It does not seem to matter where I'm connecting to. Connections to my local MythTV backend fail just as predictably as connections to, for instance, the Fedora update sites. Obviously this is extremely annoying, as it makes it impossible to use the box for its intended purpose: MythTV frontend. After a couple of seconds, every connection just stutters and dies...
Even more strangely, if I then start a ping -A 10.0.0.1 (where 10.0.0.1 is my router) in a separate window, the connection unstalls and continues, although slower, even if the stalled connection was to my MythTV backend (which doesn't go through the router). This workaround enables me to at least use the box somewhat normally, but obviously it's not ideal and should not be necessary. I've been Googling it, but I can't find any recent information about problems with stalling TCP connections in Linux.
My setup looks like this:
| MythTV Backend |
| (FC5 box) |
+--------+ | +------------+ +-------+
| MythTV | +-----+ +-----+ | NAT Router | | Cable |
|(FC5 |---| Hub | | Hub |---| / Firewall |---| Modem |
| box) | +-----+ +-----+ | (FC3 box) | +-------+
+--------+ | | +------------+ |
+----------+ +--------+ ************
| Wireless |...| Access | * Internet *
| Bridge | | Point | ************
The MythTV box is the one having the problem. It does not seem to matter whether the connection is to the Internet somewhere, or to my local MythTV backend, so I do not think the problem is with my MythTV Backend or router. Previously I had installed Ubuntu 6.06 on the MythTV box, and it did not have this problem, nor did older versions of Fedora Core, so I don't think it is a hardware problem either, or a problem with my network.
The network configuration on all the boxes is completely standard. I've made no changes to any of the settings in /prox/sys/net/ipv4 (except to test potential solutions, but none of them worked so I reversed them all). I suspect that some kind of problem in my Linux kernel is being triggered by some oddity in my network, or by one of the other Linux kernels. I'm at work now, so I can't check the exact kernel versions, but all the boxes should be completely up-to-date.
I hope all this rings a bell with someone here! Can anybody help me figure this out? Or point me to some good, detailed resources about how to go about troubleshooting this problem? Many thanks in advance!