Submit Hint Search The Forums LinksStatsPollsHeadlinesRSS
14,000 hints and counting!

A possible solution for failed DNS lookups on 10.3 Network
I just recently upgraded to Panther (yeah!), and noticed that I was getting failed DNS lookups on 80% of the websites I visit -- but only the first time. I would enter in an address and get an error message about a failed lookup or no hostname exists. I would try again and it would work fine.

After much searching, I finally found an article (Mac OS X DNS Issues on obzorg.org) that described a similar, though not identical, problem. The solution presented there seemed to work, so I felt I could share it here.

I'm behind a Linksys router that uses NAT. What I did was open up the Networks pane in System Preferences application. Then I created a new location (called "DHCP Manual DNS") which was nothing more than a copy of the "Automatic" location (DHCP defaults). Then under both Ethernet and Airport (The "Show" drop-down box), I added 192.168.1.1 to the DNS servers field. This seemed to fix the problem. So now when I'm behind the router, I have the "DHCP Manual DNS" location, and elsewhere I'm in the "Automatic" location.

Hope this helps others who use macosxhints.com as their first stop for Mac info.

[robg adds: There's presently a really long thread on this same issue on our forum site. If you're experiencing the problem, please try this solution and post here (and/or on the forums) if it works for you. I haven't had these issues, despite being behind a Linksys box running NAT -- the only difference I can see is that I don't use DHCP and instead rely on self-assigned internal IPs for all my boxes.]
    •    
  • Currently 2.20 / 5
  You rated: 2 / 5 (5 votes cast)
 
[20,730 views]  

A possible solution for failed DNS lookups on 10.3 | 20 comments | Create New Account
Click here to return to the 'A possible solution for failed DNS lookups on 10.3' hint
The following comments are owned by whoever posted them. This site is not responsible for what they say.
A possible solution for failed DNS lookups on 10.3
Authored by: Puzo on Nov 08, '04 09:33:52AM

Actually, you don' have to make new location: your system will consult IP in DNS Service field then other IPs from your DHCP or ISP. You can have multiple IPs in this field, as well - so you can also add additional IPs of any domain servers you may know about.



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: jerryg on Nov 08, '04 11:39:30AM

So If I have DSL at work and Cable at home that use different DNS servers, I could list all possible DNS servers in my setup and it would find one that worked?

TIA, Jerry



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: Puzo on Nov 08, '04 01:23:04PM

yes. your system need lookup answer, and it won't hurt to have additional sources to pull necessary answer from.



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: acalado on Nov 08, '04 10:19:32AM

You can also just use your ISP's DNS server IP addresses. A friend of mine at work was having the same problem and he said he fixed it that way. I have never had the problem because I have always thought it was necessary to input my ISP's DNS server IP addresses.



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: jdos2 on Nov 08, '04 12:08:27PM

I had problems similar to what you reported. I brought up Ethereal and found my 10.3.4 laptop querying mDNS, and failing that, the local DNS server (by then, the web page "timed out")
<p>
I've not a explanation, but setting my machine to point to the DNS servers I maintain for work got things working for me.


---
2001 Moto Guzzi V-11 Sport
1999 Triumph Trophy (Shop Bike) 1200



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: penum6ra on Nov 08, '04 12:11:23PM

http://www.codepoetry.net/archives/2004/11/03/doubledip_dns.php

This solution worked for me, and was much simpler.



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: Alidoro on Nov 09, '04 01:38:16AM

Thanks, it also worked fine here. Very useful



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: arizdave on Nov 08, '04 12:30:24PM

There is and has been a long and detailed discussion about this problem on another major mac website 'MacFixIt"

www.macfixit.com

(:-)



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: gidds on Nov 08, '04 01:33:44PM

I'm still on 10.2.8, so I haven't hit this problem. But I've had a similar one, so I know a little about this sort of thing.

Firstly, in the example above, 192.168.1.1 is the local address of your router. That won't be the right number for everyone; for example, mine's 192.168.7.1. But it'll be the address from the Network preferences 'Router' field; it'll usually begin with 192 or 10.

Secondly, a bit about what's going on. DNS stands for Domain Name Server; it's what computers use to translate hostnames like 'www.bbc.co.uk' into numeric IP addresses like 212.58.224.81, which they can then access directly.

Your ISP will usually provide a DNS server or two you can use; you can put those addresses straight into the list in Network preferences. However, I hit one issue: what if your ISP changes its DNS servers? In my case, my Mac was still calling the old ones and getting no response, so it couldn't find any web sites...

However, I found an alternative. Some routers (maybe all, I dunno) can get the DNS server addresses directly from your ISP, and can then act as a DNS server themselves, forwarding on queries as needed. I gather this is called 'DNS Relay'.

This is what this hint is doing. If your router supports DNS Relay, then you can put its (local) address into the DNS Servers list, and let it worry about finding out where your ISP's servers are, &c. That's all you need to change; and it seems to be a Good Idea(tm) whether you're having the 10.3 problem or not!

---
Andy/



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: bjackson on Nov 09, '04 12:41:07AM

Not to nit-pick, but DNS stands for "Domain Name System", the complete system of hierarchical domain name servers on the Internet.

DNS relay is fine, but hard coding your name servers shouldn't be that bad either (ISPs shouldn't be changing them too often!)

The other thing you can do is run BIND or DJBDNS locally and do your own queries.

Brian

---
--
Brian Jackson
b.k.jackson@mac.com
http://www.brian-jackson.net



[ Reply to This | # ]
Thanks!
Authored by: Pedro Estarque on Nov 08, '04 02:05:31PM

I've been dealing with this for a long time. Not anymore now !



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: u2mr2os2 on Nov 09, '04 12:43:43AM

The DHCP connection served by the Linksys router tells your Mac what the DNS servers are as part of the DHCP connection. I haven't put them in my configuration and it knows what IPs to use for DNS. What I didn't know is that the Linksys would forward DNS requests, which would be useful for my boxes using static IPs and can't get them via DHCP for when the DNS IPs change.



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: victory on Nov 09, '04 08:11:05PM
Like (all?) others, I've been having name-lookup problems under 10.3.x. However, this is happening even though I've been (and still am) using my Linksys WRT54G address for DNS lookups -- months before the current 'situation' with 10.3.x failing to resolve names properly. (For owners of Linksys and other routers that proxy DNS requests this is a convenient tip anyway. It leaves it up to the router to automatically track if/when an ISP changes the address of their nameserver rather having to specify it on all your internal clients)

So while I'm glad the tip worked for the original poster, it didn't help my setup.

Note: I've also tried the macfixit.com tip of forcing the name resolver (bind) to start up in IPv4 mode without any luck.

[ Reply to This | # ]

A possible solution for failed DNS lookups on 10.3
Authored by: g3cko on Nov 10, '04 05:12:59AM

I have a similar setup, dns server on my openbsd router, and i get exactly the same problem.

HOWEVER... I've found that setting my local dns server to use my ISP's dns IP's as forwarders seems to have cleared up the problem... I'll report back in a few hours if it seems to have fixed it.



[ Reply to This | # ]
From an anonymous reader...
Authored by: robg on Nov 10, '04 07:53:51AM
This was sent in as a hint, but it's clear it's a comment on this issue, so here it is:
This problem is completely due to the fact OSX has a very short timeout when receiving an answer from the DNS server.

I have checked it through tcpdump. I've seen that, if the DNS answer is late by some seconds, OSX returns an error to the querying app (e.g. Safari), but the answer from the DNS server arrives some seconds later. It is not then an error of DNS (and all other PC running Linux/Windows don't get any error).

It happens only the first time because the DNS is querying the Internet DNS servers to resolve the query for a new address (normally through a DNS recursion), while from the second time on it will return immediately as it has the IP address in the cache.

If you have a primary and a secondary DNS you are likely not to notice this error too frequently as OSX tries the second DNS and gives it a slightly longer timeout (I guess).

As I am behind a router/firewall, I have a single DNS address, but I configured the same address twice, in both primary and secondary DNS, and it seems that now I get the error very unfrequently, as OSX tries twice the query giving the DNS server twice the time to answer.
-rob.

[ Reply to This | # ]
From an anonymous reader...
Authored by: crarko on Nov 10, '04 09:17:19AM

I wonder if anyone knows if that timeout value is configurable, and if so, where; or is it just built in to the kernel?

It isn't in /var/run/resolv.conf, that's for sure.



[ Reply to This | # ]
From an anonymous reader...
Authored by: pdr on Nov 10, '04 09:17:41AM

After reading various comments in Apple Discussions, this was the method I tried, and I have had no problems since. I do notice an occasional brief hesitation before a site loads, but I once again have 100% connection.



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: kevin_stevens on Nov 12, '04 03:00:12AM

I only started having this problem recently - perhaps 10.3.5 or so. Just ran a tcpdump and noticed that my PowerBook was attempting to do a reverse lookup on the DNS server's IP address, attempting four times for each IP address request. Fortunately, I run my own DNS server, and correcting the reverse lookup record (which had become obsolete) fixed the reverse attempts. My reload problems went away immediately.

It's possible that the reverse lookup validation of the DNS server is a recent security-related change. If so, it could explain the varying results people are having. Just a data point.

KeS



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: ngb on Nov 14, '04 06:09:41AM

This theory would seem to be supported by my own situation. I had not had the problem prior to applying the most recent security update (the one released prior to 10.3.6), but now am having this problem on about 30% of new sites, and even on some sites I have visited before. Using the router IP address for my DNS appears to have solved the problem.



[ Reply to This | # ]
A possible solution for failed DNS lookups on 10.3
Authored by: jhegarty on Nov 15, '04 08:31:05AM

I've had 10.3 since last April, and only started getting DNS issues in the last couple of weeks ... so it must be due to a recent update.

I have *exactly* the same problem as described: sites error once, and then work the second time. Another poster suggested that this might only be with "new" sites for which the resolved address is no longer cached, but I've had the problem even with regularly visited sites (like google.com).

It's rather annoying to have to put in the DNS servers, especially for those of us on-the-go with an iBook (or PowerBook). I have no idea what the DNS servers are at work or on various open networks around campus and at coffee shops.

I suppose all we can really do is wait until there's another update out which fixes the problem.

---
--[ you cannot consistenly judge this statement to be true ]--



[ Reply to This | # ]