General discussion


Frequent losses of WAN connectivity

By thenicestguy ·
Setting: Small office with a mix of Ethernet printers, Ethernet Macs, and Airport Macs. About ten hosts.

Network config: Verizon DSL through a Westell WireSpeed modem, to an off-the-shelf Belkin router / switch / 54g access point, to a crufty old Asante hub, to a patchbay, to the walls.

Situation: Randomly, but quite frequently -- usually once or twice a week, but it has even happened more than once a day -- all systems will lose their connection to the Internet. LAN connectivity is unaffected, and I *THINK* I've seen certain Internet applications (retrieving mail from POP3, for example) continue to work, although I haven't yet been able to verify that. HTTP definitely dies.

Remedy: In each case, the problem is fixed very easily by a soft reset of the router. I can even do this through the Web-based management, so obviously the hub is working properly ?- at least after the fact.

Evidence: Exhibit A: The hub is extremely flaky, but it doesn?t seem possible that it could cause Internet outages without causing LAN outages.

Exhibit B: The symptoms are time-outs, not failures to find the hosts, so that would seem to indicate that the DNS servers are still reachable?

Exhibit C: I kept a little log of several outages, and only once out of five was the WAN IP address leased by the router the same before and after the reset. In fact, there was a point where the address changed from 151.x.x.x, to 141.x.x.x, then stayed the same, then changed back to 151.x.x.x. I?m no expert on ISP-to-ISP routing or on DHCP configuration, but doesn?t that seem weird?

Finally, the question: Can I deduce from this what the weak link is? If not, what would be a good methodology to figure it out? Unfortunately, we?re a small non-profit, so I can?t throw money at the problem. (Otherwise I would have cut that hub out of the path some time ago.) So I want to at least rule out the possibility that this is all Verizon?s fault before I try a new router.


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by NormH3 In reply to Frequent losses of WAN co ...

These problems can be very difficult to solve without accurate failure data. Apparently you are able to talk to the router during outages, otherwise you wouldn't be able to access it via the lan to do a remote reset. I think I would have to give Verizon a friendly call and discuss it with them. (the changing WAN address sounds a bit suspicious)

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by CG IT In reply to Frequent losses of WAN co ...

using a fax somewhere that's on the same line that someone uses?

Verizon changed their service levels [we have it here] and since then I've seen a lot more dynamic addresses changes than previously. Also, we have observed that if the WAN connection fails for whatever reason, you'll get a new IP address. If the westell gets powered off or the router does, or the 2 wire RJ-11 gets unpluged from the westell you'll get a new address. If theres a bug in the Belkin firmware that causes a soft reboot [we had that problem on a Linksys]you'll get a new address. If you get a overloaded on inbound that causes the router to put shields up, you'll get a new address [we have this feature on a Linksys that with a DoS attack at a certain threshold, will block all inbound], and it appears that if any of all that junk I outlined happens, the router doesn't get to send out the ACK message out to the ISP DHCP so until you reboot, you don't get an address. We also had someone hook up a fax and use it over the DSL line [hired help] which caused a whole lot of problems.

the hub prolly isn't the way to go. Some switches are cheaper than hubs these days. A hub throws out packets to everyone.

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by thenicestguy In reply to

When I'm able (or forced) to do some remodeling of this network, the hub will be the first thing to go.

Fax machine is on a dedicated line.

So my outages are caused by some undetermined phenomenon that's causing Verizon to reset my address, and the router not coping adequately. Is this a deficiency of the router, or is that just the way it is? Either way, I guess I'd better talk to Verizon.

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by Monice In reply to Frequent losses of WAN co ...

I've actually had a somewhat similar issue with DSL internet being flaky.

Here are my 2 cents:

1. In the Westell modem make sure that your dsl connection is set to always on and not connect on demand.

2. Make sure that in your switch/router (assuming it's a dsl router) that the idle connection time is set to 0 (zero).

These two simple settings made a world of difference for me.

Hope this helps.

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by Chorito In reply to Frequent losses of WAN co ...

I agree with Answer 3...

When you experience the problem...don't reset the router...connect to the router and ...if the router has logs..look at the router logs and status for any errors.

Check the modem to see if the Sync and PPoPe link lights are on...

I come across this a lot with the westell and Netopia modems. Everything seems to be setup right but, the modem can't resolve the ISP DNS. And resetting the modem once and sometimes a few times fixes the problem. I've even had to reset the modem with the computer off then turn the computer on to fix it.

It has to do with the modem and the ISP WAN. The ISP does something or changes something that the modem can't handle, doesn't know how to handle or thinks it's handling it right...

Talk to your ISP and see if they will send you a modem from a diff mfg.

Here in S. Florida the only DSL ISP that I have come across that really haven't had any real annoying problems is BellSouth. All my clients with BellSouth DSL don't have these annoying problems. But, they do pay more...

Hope this helps...

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