linksys router not forwarding DNS properly?

[VirtualLarry]

Just wondering, I'm at a coffee shop, and according to the woman working there, they have a Comcast connection, and what appears to be two routers. One Linksys, one Belkin, both G.
She unplugged and reset them, no change. Windows 7 reports "no internet", and a further troubleshooting mentioned primary DNS server failure, and wireless router failure.

Seeing the mention of DNS, I manually configured the IPv4 properties on my adaptor, and set my DNS to 4.2.2.2. Then the connection came up fine, no problems with internet.

What causes this? I've heard of other cases in which the router didn't forward DNS properly, and I think I recall it was also a Linksys.

I told her to tell her management to investigate DD-WRT -capable routers.

Oh, I tried connecting to the Belkin, I got Limited Access according to Win7.

 

[owensdj]

It sounds like the routers aren't giving out IP addresses to client machines correctly. Why do they have two routers?

 

[freegeeks]

did you try an nslookup when you have these problems? Try to manually configure the opendns servers.

 

[VinylxScratches]

Maybe there's a DHCP clash between the two routers?

If DNS is the issue can you resolve google.com by using IP?

Does DNS show up in their web console?

 

[Nothinman]

What causes this? I've heard of other cases in which the router didn't forward DNS properly, and I think I recall it was also a Linksys.

I wouldn't be surprised if it's just normal shittiness that you get with cheap SOHO routers. IMO they're just too unreliable, I'd rather spend the extra hour or so to build a Linux firewall or setup a PIX/ASA than deal with one of those.

Maybe there's a DHCP clash between the two routers?

If they're both accessible and work individually it shouldn't matter which one gives you the address. Sure they should be fixed and setup properly, but it shouldn't cause the issue the OP is seeing.

 

[RebateMonger]

I've seen cases where a SOHO router wasn't working correctly as a DNS proxy server (or whatever you call it when you tell client PCs to use the router as the DNS server). In a network with no internal DNS server, it's safest to set all the client PCs to directly access an external DNS server.

 

[JackMDS]

This issue can appear as a trouble in different ways, depending on the "Plastic Box".

Many times the solution is to set the WAN port of the Router with 4.2.2.2 or OpenDNS or other reliable public DNS, or setting the computers directly with the DNS (as mentioned by RM).

Personally, I prefer the Router WAN side of it working well.

BTW, any one who is curious about their DNS.

Try this little free application, http://www.portablefreeware.com/index.php?q=dns&m=Search

Click on the screen shoot to see example of what it does.

 

[VirtualLarry]

An update. I finally got a chance to talk to the owner. He has a Cisco/Linksys RV082 VPN router facing the cable modem, with a static IP set up with the ISP. He has 4.2.2.2 and 4.2.2.3 punched in under the DNS settings on the router. I asked further, and he has another router acting as an access point, which he said he configured statically with a 192.168.x.x, and claimed he punched in the DNS into that one as well, and has DHCP enabled.

So, now that I think about it, that sets off a red flag for me, if he wired the "access point" router using a LAN port, rather than the WAN port, then that might cause a DHCP conflict.

He had a desktop machine there, which I assumed was wired in, but I didn't physically check, it might be wireless too, that could access the internet. I didn't check if he had manually entered DNS into that computer too.

I didn't have much time, perhaps I'll get a better chance to get a full overview of the network and settings in the future. I just happened to catch the owner there about 30 minutes before they closed.

 

[VinylxScratches]

Are you getting paid for this lol.

 

[VirtualLarry]

No, although he offered me some free coffees if I get it fixed.

I was there the other day, and I couldn't even pull an IP from the router, I ended up with a 169.254.x.x link-local address that Windows 7 auto-assigns when DHCP fails.

Which was kind of wierd, since the girl working there had her laptop connected to the internet over the wireless.

I put my computer to sleep, and then woke it up, and then it started working. Strange.

 

[VirtualLarry]

Well, I finally figured out it, with assistance from the owner. There were two settings that were amiss.

The RV082 has two places for the DNS settings, it turns out. There was the main setting, and then there was another setting under DHCP.

Speaking of DHCP, he had set the number of leases to 10, which turned out to be not enough. He already had a number of machines connected there, and they ended up filling up the DHCP pool.

The "other router as an access point" turned out to be a Linksys WAP54G. So there was no DHCP conflict as I originally suspected.

Btw, anyone want to comment on PCI compliance issues, with having a wireless access point on the same internet connection used for CC transactions?