Hi. I am not yet a Linux expert, but have learnt a lot. I have been using Linux for the past six months, have begun to have the same problem with Linux web browsers as I had with Windows Explorer. Mozilla and Lynx work fine for the first half hour that a system is running, then they are unable to connect to remote host. I know your first guess might be my ISP, but I have checked connection problems and the times I lose connection do not match the times they report connection problems. I have tried almost ever tool, pin, traceroute, dig, route, and all give me the result that my system can not connect to my host.
I am totally lost as to why this happens. The engineers at the ISP know less than I do and when I tell them I am using Linux, I hear a "uhmm I will transfer you now" and I get someone running me through the basic sys admin tools. Eventually they say "I don't know" and tell me to do a reinstall of my system, which I have done a dozen times. Someone even had the cheek to say "If you buy a windows licence, we could get your connection to work." My connection works, if I can get http and ftp to load for an hour then I can get my lan to work, what I need is for my connection to keep on working, without restarting every box and making myself look like a idiot.
I can put this all down to one of three things, 1. My ISP is useless and I should change, 2. I am dork and am typing rm / every time I boot up, 3 . Windows and Linux can't maintain a stable connection on my box, 4. My flagship box is cursed and I need to burn it on a stake and buy a sun system.
I don't know if this helps but I have had a few errors. Firstly on reboot my NMB services fail and shutting down SMB services fails, on update and install I always get errors with the file tight-vnc, can't remember entire name.
I will cherish any usefull advice on this issue.

Well, it's not NMB on startup, SMB on shutdown (both have to do with Samba iirc), or tight-VNC (that's an app for sharing desktops in remote virtual windows).

One thing I can think of would be a timeout on something from the ISP's end. If you can, consider having the connection re-initialize on a timed basis.. maybe every half hour or something. Or possibly on-demand with a traffic timeout. It could be your modem, but sounds like it's something on either the connection itself or the way it's being accessed.

A similar situation I've seen is where ADSL providers expire DHCP leases prematurely while they're still connected.

Good luck!

How do I get a connection to re-initiate the connection every number of mins. If my ISP servers are cutting me of, when I don't use them for a while, then I will be upset.
I recall having the same problem on my ms box. Should I just change my ISP?

Well, it doesn't sound like a bad idea. Especially if the Linux and Windows machines use different modems.

As for having the connection reconnect itself, that depends on how your establishing it. If it's a system process you could probably do a "ifdown ppp0" then "ifup ppp0" in a cron script.

Basically, you just need to tell whatever is running the connection to shutdown and kick up on a timed basis. If you need help with that post what you're using and someone's bound to know if I don't .

I am using a cable modem, so it should be on all the time. I must admit I do not think I had this problem for the first month or so after installing linux, and I could leave my computer on for half a day and the browser would still connect. I installed some software, including tripwire and it started after that.

Oh! Well, that's actually a whole different deal.

Cable Modem's aren't a "modem" at all. Rather, they're a (hopefully no one will beat me if my terminology is wrong) bridge for a cable line, converting the signal over and offering up an ethernet or USB TCP/IP connection. This would be similar to the DSL problem I ran into. Sorry about that.. I think I subconsciously filter the "cable" out of "cable modem"

It sounds like something is timing out somewhere along the line.. possibly due to a misconfiguration of one of those security utilities. Tripwire's a bit nasty in that it will deny address's.. which could lead to your provider taking your connection offline if they don't see that it's up.

First try running "dhclient eth0" or "dhclient-script" (if that's what MDK 9.1 still uses) or possibly "dhcpcd eth0". This is all assuming you've got that cable modem plugged into an ethernet card and that it's the first one. This should request new settings from the DHCP server they run and test if it's a timeout there..

To bring that connection down and up "/etc/init.d/network restart" should work. If it suddenly starts working after either that or the DHCPD restart either they're timing out your connection somewhere or you've got something misconfigured.

Are you using a router of some sort (external/internal)? That may cause a problem due to a hardware defect or a software scripting error.

Thanks for advice inhibit. I tried dhclient eth0 and everything looked okay. I will wait till my connection goes down then try the command to see what I get.
NetAX I don't have an internal router, as for external routers, do you meen routers on the WAN? I figured everyone does.

Maybe a problem with your modem?