my router sucks at dns

ksp7498 · Posted: Mon Apr 13, 2009 2:41 am Post subject: my router sucks at dns

For a while I've been having an issue where my linux boxes (but not windows boxes, for some reason) took unusually long to resolve dns names. It would take several seconds to resolve each website, while my 1 windows machine would always resolve instantly. Well finally, on a hunch, I checked /etc/resolv.conf on my linux machines (they all use dhcp) and I noticed that the router was assigning itself as the first dns server. Sure enough, if I removed 192.168.2.1 (the router) from /etc/resolv.conf and just left the 2 "real" servers, then dns resolved instantly like it should.

I used dhcp_ethx=( "nodns" ) on the machines so I could override the dhcp settings, and all was good. But there's one problem: one of my machines is a laptop. When I take it somewhere else and connect to another network, won't I need to have new dns servers assigned? How can I make my laptop work correctly on other networks, but still have the "fixed" dns servers on my own network? Anyone have any ideas? Is there a way that I can blacklist 192.168.2.1 as a dns server or something?
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cyrillic · Posted: Mon Apr 13, 2009 12:26 pm Post subject:

Check your router's configuration to see if it has a "DNS proxy" or "DNS forwarding" setting, and turn it off.

I had the same problem with one of my old routers. Eventually I tossed it, and switched to an old Gentoo box with 2 NICs, and I haven't looked back since.

ksp7498 · Posted: Mon Apr 13, 2009 3:02 pm Post subject:

yeah I used to use a gentoo box + switch as my router, but I wanted to reduce the power usage and noise so I picked up this Belkin router a few months ago. After some googling, it seems as though I'm not the only person with this issue, although Belkin denies that their router broadcasts itself as a DNS server. Me, and a bunch of other people on the internet, beg to differ.

It looks like I may be reinstating my gentoo router. I looked all over the place in the router's configuration and I can't find any way to disable this behavior.
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Inodoro_Pereyra · Posted: Mon Apr 13, 2009 4:53 pm Post subject:

ksp7498 · Posted: Fri Apr 17, 2009 2:36 am Post subject:

cach0rr0 · Posted: Fri Apr 17, 2009 3:45 am Post subject:

i use opendns as well - for speed, as well because i can do very basic content filtering over at the parents' house (heaps of nieces and nephews using their systems, which, i force-fed them a healthy dose of linux for security reasons)

my cheapy little linksys WRT54GS allows you to define which DNS servers it pushes out on DHCP hosts
i dont know if youre talking a proper sophisticated route or which, but that works for me
I have it push out 208.67.22.222, 208.67.220.220 as the dns servers. Dunno if your router has similar, but worth looking into.

Meaning, on your router, if you dont wish to use opendns (say you have internal resources published in DNS that wont be resolvable using opendns), set it to push out your internal name servers.

poly_poly-man · Posted: Fri Apr 17, 2009 3:54 am Post subject:

wow... opendns? the very thing I have spent frustrating hours cursing at on other people's systems?

My desktop happens to be a DNS/DHCP server for the rest of my network, as well as providing a few other services...

the one thing I discovered that I will continue to do, even on a laptop and whatnot... install bind on the machine with issues. It will ask root-servers (and up the tree), so you get guaranteed accurate information, no junk like the random crap opendns does (searching for invalid queries? wtf?), and, as an added bonus, insanely better speeds due to smart caching (after you hit it up for a host once, it will remember it for a while - then you are only asking you local computer at nearly zero lag for the name service most of the time, rather than a faraway server every time.

it is the best thing I have ever done.
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MaximeG · l33t Joined: 15 Apr 2008 Posts: 722 Location: Belgium

Hi,

Had the same issue in the past.
I didn't solve it, but turned to static IP instead.

Will try to disable the DNS broadcast anyway.

Regards,
Maxime
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minor_prophets · Apprentice Joined: 07 Oct 2007 Posts: 281

ksp7498,

Can you post the model router you have had issues with so that others may avoid purchasing the same thing?

Thanks,

MP

my 2cents, djbdns is the route I went on a machine I'm using as a server. The setup was ridiculously easy and virtually admin pain free.
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MaximeG · l33t Joined: 15 Apr 2008 Posts: 722 Location: Belgium

@minor_prophets

Would be a nice idea indeed, but I'm afraid there is not only one routeur in the case

Regards,
Maxime
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minor_prophets · Apprentice Joined: 07 Oct 2007 Posts: 281

Yeah, I hear ya.

I've got 2 wrt54gs with dd-wrt firmware on both of them. What a tremendous difference over the weak, weak, weak, sucky VxWorks firmware Linksys ships these things with.

The wrt54gs do there job well, but I'm really looking into using my Jetway VIA C7 book-size mini-itx for routing, firewalling, dns/dhcp, squid, etc. Problem is noise. While the model I have is purported to be "fanless", to remain consistently cool it needs at least one of the two case fans which are ridiculously loud. So loud that if I have one plugged in, adding the second make little audible difference. I bought Silex fans thinking they were small enough. They weren't. I really need to find tiny quiet fans.
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poly_poly-man · Posted: Fri Apr 17, 2009 1:34 pm Post subject:

minor_prophets · Apprentice Joined: 07 Oct 2007 Posts: 281

@poly_poly-man,

At the moment, a server machine is doing dnscaching for my entire network. Works out pretty well in combination with squid for all the machines I have.
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poly_poly-man · Posted: Fri Apr 17, 2009 1:48 pm Post subject:

wuzzerd · Guru Joined: 05 Jan 2005 Posts: 467 Location: New Mexico

I've had these issues for several years with the ActionTec modem sold to me by the phone co. Like poly_poly-man I just install bind, especially on laptops, since the local coffee shops use the same junk modems.

These use Linux, but I have yet to see a listing of the QWest version.

MaximeG · l33t Joined: 15 Apr 2008 Posts: 722 Location: Belgium

Hi,

Would I be bold and ask for what you use for _local_ DNS solution ?
Yes, I must admit I suck at networking, but I don't mind learning :p
If you have a good local (to install on one of my machine) dns solution (at least names for this solution) I'd be interested to try.

Regards && thanks,
Maxime
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poly_poly-man · Posted: Sun Apr 19, 2009 1:39 pm Post subject:

MaximeG · l33t Joined: 15 Apr 2008 Posts: 722 Location: Belgium

Hi,

Nah, I mean : DNS caching for Internet.
Like, the first time I want to reach a link it has to download the actual target from the name, then the second time I want to reach it, it would be a local request.

If I'm not blind I've seen it in the thread.

Regards,
Maxime
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poly_poly-man · Posted: Sun Apr 19, 2009 2:34 pm Post subject:

Simba7 · Posted: Sun Apr 19, 2009 3:39 pm Post subject:

minor_prophets · Apprentice Joined: 07 Oct 2007 Posts: 281

overkll · Posted: Mon Apr 20, 2009 6:17 pm Post subject:

What? No mention of dnsmasq? I'm surprised. Personally I use bind, but dnsmasq is easy for beginners. Tomato router uses it and I wouldn't be surprised if DD-WRT uses it as well. It can also do DHCP.

dnsmasq is available in portage.

poly_poly-man · Posted: Mon Apr 20, 2009 6:47 pm Post subject:

dnsmasq sucks. there's no caching, and you get dns exactly as bad as another server that you point it to.

and the dcp from that isn't that great either...

...ntm neither part has good configurability.
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overkll · Posted: Mon Apr 20, 2009 11:45 pm Post subject:

Did I hit a nerve? LOL. I've never used dnsmasq, so I can't comment either way. Just thought I'd throw it out there.

poly_poly-man · Posted: Tue Apr 21, 2009 12:06 am Post subject: