Solved: Embarrassing Problem concerning a router and a switch.

[epsilon]

I'm a full time System/Network admin, but I have to confess I am completely stumped. I'm embarrassed to say that I am at a complete loss.At home I have a wired network sprawling my house and need to add a wireless router so that some of my wireless devices (laptop, IPhone, etc) can access the network.

Whenever I connect either of my Linksys WRT-320N, DLINK DIR-655 or trendnet router it is sometimes a matter of seconds or minutes before all wired devices connected to that router including the upstream switch drop out (link lights stays on).

I have looked everywhere for a network loop, but can find none. I am aware of no wireless devices that are connecting and bridging to a wired portion of the network.

 

[ecom]

Are you connecting these wireless routers on the WAN side or LAN side?

Did you turn off DHCP?

Not sure if you've come across a user putting a home router device on your network yet. But it sucks trying to find that thing. It knocks lots of people offline due when the rogue DHCP server starts giving out IPs.

 

[epsilon]

Good question. Indeed I turned DHCP off on the router and made sure I am not using the public facing interface on the router. I only run a DHCP daemon on my OpenBSD firewall.

Are you connecting these wireless routers on the WAN side or LAN side?

Did you turn off DHCP?

Not sure if you've come across a user putting a home router device on your network yet. But it sucks trying to find that thing. It knocks lots of people offline due when the rogue DHCP server starts giving out IPs.

 

[theevilsharpie]

I've seen this happen on wireless access points/routers that were configured as wireless repeaters.

 

[epsilon]

I am making sure that only 1 router is on at any one time. I have not configured any of them as repeaters and I doubt that they ship this way.

I've seen this happen on wireless access points/routers that were configured as wireless repeaters.

 

[Tbirdkid]

ip conflict?

 

[RadiclDreamer]

ip conflict?

arp -a and see if the correct mac is being shown for the gateway

 

[spidey07]

Sounds like a bridging loop. Make sure no machines are bridging their wireless and wired cards.

Easiest way is to load wireshark on a machine and take a look at the trace. If you see the same broadcast and multicast frames constantly, you have a bridging loop. SOHO stuff doesn't run spanning-tree and it's real easy to cause one with them.

Ditto on the IP conflict or perhaps proxy arp is enabled on one of the routers.

 

[epsilon]

Did the wireshark capture from my Ubuntu box. I didn't see any broadcast storms. I have double checked all the hosts in my house. All are wired except for my laptop and my Mac Mini which is booted into Windows with the wireless interface disabled.

Sounds like a bridging loop. Make sure no machines are bridging their wireless and wired cards.

Easiest way is to load wireshark on a machine and take a look at the trace. If you see the same broadcast and multicast frames constantly, you have a bridging loop. SOHO stuff doesn't run spanning-tree and it's real easy to cause one with them.

Ditto on the IP conflict or perhaps proxy arp is enabled on one of the routers.

 

[epsilon]

Solved:

Friends don't let friends buy Fry's branded switches. It turns out that a Fry's branded switch (manufactured by Sheky-Data inc.I beleive) which was the attached switch was the culprit.

 

[Tbirdkid]

If it was the culprit, please give us more info. Just the fact that the switch was the culprit doesnt give us the end story... hook us up and dont leave us hangin! lol