What do you do when Linksys tech support is utterly useless and refuses to help?

[RebateMonger]

Originally posted by: Fraggable

One more thing, I've seen about 5 PCs actually get the 192.168.x.x IPs, and about 5 others that get a 169.x.x.x IP - I know that's a self-assigned one. It could have been a fluke thing that they assigned themselves 192.168.x.x and were not actually getting that assigned to them.

I'd say there's zero chance that a PC would assign itself an IP address of 192.xxx.xxx.xxx. It's going to be a 169.xxx.xxx.xxx address or nothing.

Any XP computer that's receiving an IP address from a DHCP server will list the IP address of that server in it's TCP/IP properties.

 

[Fraggable]

Originally posted by: RebateMonger

Originally posted by: Fraggable

One more thing, I've seen about 5 PCs actually get the 192.168.x.x IPs, and about 5 others that get a 169.x.x.x IP - I know that's a self-assigned one. It could have been a fluke thing that they assigned themselves 192.168.x.x and were not actually getting that assigned to them.

I'd say there's zero chance that a PC would assign itself an IP address of 192.xxx.xxx.xxx. It's going to be a 169.xxx.xxx.xxx address or nothing.

Any XP computer that's receiving an IP address from a DHCP server will list the IP address of that server in it's TCP/IP properties.

I know it's not supposed to assign itself a 192.168.x.x IP, but I've seen a lot of really weird things happen and I don't think it's out of the realm of possibility. Some of these teachers take their laptops home to use on their wireless networks and that may have something to do with it.

 

[azev]

let say, you remove all the router/wap from your network. Do you still have the same problems ? If not, do you have the budget to purchased new soho grade pure wap not some hybrid router and wap function ?
Its possible that multiple router on the same network doesnt play very nicely with each other.

 

[Fraggable]

Originally posted by: azev
let say, you remove all the router/wap from your network. Do you still have the same problems ? If not, do you have the budget to purchased new soho grade pure wap not some hybrid router and wap function ?
Its possible that multiple router on the same network doesnt play very nicely with each other.

If we remove all the routers from the network, we still have to power cycle the gigabit switch at the server to bring the network back up.

One interesting thing I've noticed in the last few hours, our networked printers have been giving us fits, sometimes they work, sometimes they don't. I did a persistent ping to one of the problematic printers (ping 10.0.0.xxx /t) and it worked for a minute or so, then I got about 20 timeouts, then it worked again. I think something is flooding the network and a certain interval - maybe this is what massed up the routers.

 

[Fraggable]

I've got Ethereal running on our server and am able to capture packets and all. Can I get some help setting up a capture session to figure out this broadcast storm?

EDIT: here's an example of one of my bad packets, maybe someone will see something helpful here:

pic

The 10.0.0.2 is our server's IP here, and the 10.0.0.60 specified in the pic is a Win XP system on the network.

 

[spidey07]

Just start it when the problem occurs. You select the network interface you want to capture off of underl capture options, then click "start capture". Let it run for a few minutes then click stop and save the file for analysis.

 

[Fraggable]

I've been capturing a minutes' worth of data every few hours and looking it over, it seems like most of the bad packets occur between one client PC and the server. The client PC will send a few packets, usually an internet URL or such, then follows a few thousand packets between the PC and the server. The packets from the PC to the server are all good, but all the packets form the server back to the PC show up with the checksum error.

As a matter of fact, every single bad packet in the analysis is coming from the server, and very few packets sent from the server are not showing up with checksum errors. Could this be a bad netowrk card or is it an indication of something else?

 

[OCedHrt]

One simple way to see if the wireless routers are accessible on the network is to simply try to load up their configuration page. Given your network settings, and assuming a proper subnet mask, they should not be accessible. In that case there is no way that any of the clients are getting their ips from the wireless routers.

You also mention that the gigabit switch needs to be restarted to bring the network back up, which may point to a problem around that area.

And the wireless lights being off on the routers simply means no wireless devices are connected, so disconnecting and reconnecting the network cable to the wireless routers of course isn't going to turn that light back on.

It seems to me that maybe the wireless on the wireless routers are simply failing (interference with each other?) and the laptops are losing the connection, and falling back to 169.x.x.x addresses or maybe preconfigured alternative 192.x.x.x addresses. I have a POS Dell wireless router where its wireless will lock up randomly.

Try to configure the wireless routers to operate on different channels (only 1, 6, and 11 I think are discrete from each other). Basically, for two routers that overlap in coverage, configure them to be 1 and 11, if 3 overlap, use 1, 6, and 11. If more than 3 overlap, you have too many wireless routers anyways

A couple other things. Unless you guys are actually using NetBIOS, you probably want to turn it off on all your systems. And I'm not sure just how important/relevant the checksum mismatch is on outgoing packets. After all, you're sniffing on the NIC that is sending bad packets. Does the NIC even listens to its own broadcasts? That would mean the checksums are bad before it even leaves the NIC. Try running the sniffer on the client as well and see if the packets it recieves from the server have back checksums.

 

[Fraggable]

Originally posted by: OCedHrt
One simple way to see if the wireless routers are accessible on the network is to simply try to load up their configuration page. Given your network settings, and assuming a proper subnet mask, they should not be accessible. In that case there is no way that any of the clients are getting their ips from the wireless routers.

You also mention that the gigabit switch needs to be restarted to bring the network back up, which may point to a problem around that area.

And the wireless lights being off on the routers simply means no wireless devices are connected, so disconnecting and reconnecting the network cable to the wireless routers of course isn't going to turn that light back on.

no, the wireless light is supposed to stay on solid as long as the wireless broadcast it turned on. It never flickers.

However, we have since taken all the routers down and replaced them with Netgear-G WAPs. I know, they're not the grade that was recommended, but we needed a fix now and couldn't get a Cisco product locally. We're still looking into finding a vendor but having a hard time with it.

It seems to me that maybe the wireless on the wireless routers are simply failing (interference with each other?) and the laptops are losing the connection, and falling back to 169.x.x.x addresses or maybe preconfigured alternative 192.x.x.x addresses. I have a POS Dell wireless router where its wireless will lock up randomly.

Try to configure the wireless routers to operate on different channels (only 1, 6, and 11 I think are discrete from each other). Basically, for two routers that overlap in coverage, configure them to be 1 and 11, if 3 overlap, use 1, 6, and 11. If more than 3 overlap, you have too many wireless routers anyways

All WAPs and routers are (and were) on channel 11 and worked great that way. I don't think that was the problem or they wouldn't have worked at all. As far as overlap, It's almost impossible to tell where the signal from one ends and the next begins because the Linksys wireless utility is useless and doesn't work right on Win 98 so I can't tell which I'm connected to. When we start rolling out these new laptops next week I'll have a better idea of our coverage.

A couple other things. Unless you guys are actually using NetBIOS, you probably want to turn it off on all your systems. And I'm not sure just how important/relevant the checksum mismatch is on outgoing packets. After all, you're sniffing on the NIC that is sending bad packets. Does the NIC even listens to its own broadcasts? That would mean the checksums are bad before it even leaves the NIC. Try running the sniffer on the client as well and see if the packets it recieves from the server have back checksums.

I ran the sniffer from my PC, which is a desktop using a PCI wireless card, and it couldn't capture anything. Might have something to do with it being wireless. I'll try it on one of the computer lab systems as soon as I get the chance. I just found out our language lab isn't working so my next few hours are gone

 

[nweaver]

turn TCP Checksum Offload setting to off (in the NIC properties of device manager) to fix that one packet (I would guess) assuming now that your server is GigE. I don't think that will fix all your issues.

 

[Brazen]

Originally posted by: Fraggable
Here's the situation. I have 1 Win 2003 server, 7 24-port switches, 10 Linksys Wireless-B Access points, 5 Linksys WRT54GX2 routers, 150+ PCs.

The 5 WRT54GX2's are configured as access points with DHCP turned off, manually configured static IPs, etc. However, when our network gets busy at least one of the routers will decide to turn on DHCP and consequently takes the entire network down, no one can obtain a valid IP. We have had 2 of the routers replaced under warranty, made sure all routers are on the newest firmware, etc. and they persist in doing this.

I just spent the last hour playing the phone transfer/hold/transfer/hold game with tech support. we went through configuration for one of the really bad routers and of course it works fine when we're done, but it will do this again when we get busy.

So, anyone have any ideas? I can forget about getting help from Linksys, they refuse to replace this router, much less give me a different model.

I know, we should buy Cisco products. But we're an educational facility, we don't have the budget for really expensive equipment.

Anyone have any ideas? I'm not whining, just wondering if anyone has a product suggestion, something they're using that's reasonably priced and reliable with good support.

You might try using dd-wrt on your linksys routers.

 

[Fraggable]

pray tell what dd-wrt is? custom firmware?

 

[Rapidskies]

Drop in a different switch to test with temporarily. Sounds like you have a cableing or switch issue.

 

[Brazen]

Originally posted by: Fraggable
pray tell what dd-wrt is? custom firmware?

yeah, it's a different firmware. google for it.

 

[OCedHrt]

no, the wireless light is supposed to stay on solid as long as the wireless broadcast it turned on. It never flickers.

You're probably right, but the wireless light on my dell router never flickers either. But it's off if I don't have anything connected.

All WAPs and routers are (and were) on channel 11 and worked great that way. I don't think that was the problem or they wouldn't have worked at all. As far as overlap, It's almost impossible to tell where the signal from one ends and the next begins because the Linksys wireless utility is useless and doesn't work right on Win 98 so I can't tell which I'm connected to. When we start rolling out these new laptops next week I'll have a better idea of our coverage.

Wireless networks can stall if interferred with. I can design a router firmware to kill all wireless networks it comes across simply because of the way the wireless specifications are defined. There probably isn't a better way either. Collisions have to be avoided and cannot be detected. You're better off alternating your channels between 1,6,11 even if you're not having problems now. Two routers functioning on the same channel will suffer greatly in performance if they don't just lock up outright.

 

[Fraggable]

Originally posted by: OCedHrt

no, the wireless light is supposed to stay on solid as long as the wireless broadcast it turned on. It never flickers.

You're probably right, but the wireless light on my dell router never flickers either. But it's off if I don't have anything connected.

All WAPs and routers are (and were) on channel 11 and worked great that way. I don't think that was the problem or they wouldn't have worked at all. As far as overlap, It's almost impossible to tell where the signal from one ends and the next begins because the Linksys wireless utility is useless and doesn't work right on Win 98 so I can't tell which I'm connected to. When we start rolling out these new laptops next week I'll have a better idea of our coverage.

Wireless networks can stall if interferred with. I can design a router firmware to kill all wireless networks it comes across simply because of the way the wireless specifications are defined. There probably isn't a better way either. Collisions have to be avoided and cannot be detected. You're better off alternating your channels between 1,6,11 even if you're not having problems now. Two routers functioning on the same channel will suffer greatly in performance if they don't just lock up outright.

We tried setting a few of them to channel 6 and couldn't get our old USB and PCMCIA adapters to connect. You really wouldn't believe how crappy the drivers are for Win 98. The utility doesn't work at all and locks up Windows sometimes, but without it installed the adapter won't even look for a network.

I'll try playing around with the channels once we deploy all the new systems, I'm sure they won't care what channel they're on.

 

[OCedHrt]

While not directly related to the problem you're having now, but as a future heads up, try sticking to one brand for wireless APs and clients. Many consumer grade wireless hardware have been found to be slightly non-standard compliant to gain a marketable performance edge that interferes with wireless hardware from other brands. The wireless nightmares that people have setting up their home network usually comes from a mix of wireless hardware. This is usually limited to the chipset used by the hardware.

 

[vorgusa]

I know my linksys router has the option of being a gateway or a router in the advanced router settings (near where the RIP setting is) it says to use it as a router if it is on a network with other routers and the default setting is on gateway instead of router. You might want to try changing that. You also might want to look into WAP that will let you move from one area to another.. I have not messed around with a network with multiple WAPs but I thought an advanced feature of newer ones are the ability to move from one WAP to another without having to reconnect.

 

[nweaver]

Originally posted by: vorgusa
I know my linksys router has the option of being a gateway or a router in the advanced router settings (near where the RIP setting is) it says to use it as a router if it is on a network with other routers and the default setting is on gateway instead of router. You might want to try changing that. You also might want to look into WAP that will let you move from one area to another.. I have not messed around with a network with multiple WAPs but I thought an advanced feature of newer ones are the ability to move from one WAP to another without having to reconnect.

two things, WDS, wich means no reauth when roaming, and then there are things like CCKM fast roaming, where a roam takes 250ms or less (iirc) and there is now key exchange

 

[Fraggable]

We've been seeing so many issues with our network over the last couple of weeks that I decided to trace our network and see for myself how the place is wired. I was unpleasantly surprised.

I found that the server is wired to a 8-port gigabit switch. 4 of those ports were wired to 4 24-port switches in the server cabinet, 1 was wired to a port on the 1st floor which had one of our problematic WRT54GX2's on it, 1 was wired to the fiber link to the other building, and 1 went somewhere else, like a PC sitting next to the cabinet that we use to update our sign out front. The link to the data closet was running from a random port on a random switch in the server cabinet to a random port on one of the switch in the data closet, giving us - I'm assuming - a 100 mbps connection to that closet. Even worse, each of the 4 switches in that closet as well as 2 more 24-port switches I didn't know existed were daisy-chained together using random ports, so all 120+ PCs connecting through that closet used that 1 port to communicate back to the server.

I wired it so that the gigabit switch in the server cabinet was wired directly to another 8-port gigabit switch in the closet, which is wired to each of the 24-port switches independently, no more daisy-chaining. I also found 2 more 24-port switches in the basement and in the library and wired them independently to the new gigabit switch. Needless to say, there's a world of difference. We still had an issue with a color laser printer that was wired into one of those switches, but I put it on its own port on the gigabit switch and it's been fine, so I'll have to do a little more investigating to figure that one out.

As far as the WAPs go, I was unable to convince my supervisor of the need for those Cisco WAPs. We ended up with a few Netgear wireless-G WAPs and we have 2 more Wireless-G MIMO RangeMax WAPs on order. So far they're working great, I just can't seem to figure out how to change the SSID on 2 of the 3 of them, for some reason the field for selecting your contry is greyed out so I can't change the channel or SSID name. I'll have to contact Netgear about that.