And the Risk of asking about the simplest and non DNS
 

RE: And the Risk of asking about the simplest and non DNS...

Did you try swappping IPs with one of the Windows boxes (known working bet access).

Although Both Mac and PC are capable of on the Fly Ip changes (sake of argument reboot both).

*If I had to take a guess you have a system out their that scummed your Macs Ip Address.

There of course could be better more DNS oriented explanations but until you elimate the IP as a possible issue, or it could be like banging your head against a wall.

I think you can go to the port configuration and uncheck the ethernet port then apply changes then check it and apply the changes again. This will turn the ethernet off and then on again and it should get a new dhcp lease. Simmilar to the ipconfig /renew in windows. That might keep you from having to restart the whole machine.

Have you tried entering the dns servers manually on the mac, under the network prefs? It could possibly be the setup of the dhcp server on the linux box. Check your /etc/dhcpd.conf file and make sure your dns servers are entered correctly. There should be a line like this one.

option domain-name-servers 0.0.0.0, 0.0.0.0;

where 0.0.0.0 is one of your dns servers. By entering them directly into the network prefs it won't matter if the dhcpd on the linux box is correct. I have a linux gateway setup and I had the same problem now that I think about it. It uses a program called dnsmasq which if I understand right it acts like a dns server by caching dns requests, if it doesn't know the answer it forwards it to the real dns server, but I always had trouble with my macs until I added the line option domain-name-servers to the dhcpd.conf file on the linux box, or manually entered the dns servers on each of my macs.

When you have the problem on your mac go to the terminal and type cat /etc/resolv.conf to see if the dns servers are listed in that file, they should be there.

anthlover:

I didn't swap IPs yet, but that might indeed be worth a try. I'm not quite sure if I understand what you mean by that. You mean another system in our network interfering with my system? The possibility of that would be very small since I also had the problems with only one other system up (beside the Linux box of course). This is our Filemaker Server which is also using TCP/IP and with which I can communicate without any problem. So I'm still guessing this is a DNS issue. I remember once having read about problems with the way Mac OS X is doing its DNS queries but I couldn't find it.

keithcal:

We use static IPs and I think anthlover adviced me to reboot just to be sure although it should be the same as deactivating and activating the interface.

Hey kethcal, editing your post while I'm answering is confusing... ;-)

The linux router doesn't provide any DHCP services (yet).
I already checked /etc/resolve.conf. Looks just fine.

If you do an nslookup on the same machine for an (name) address that you cannot connect to from your web-brower, do you get an address or is the address unknown?

And have you flushed your arp cache?

As I said, manual lookups work fine AND I can reach the domains via their IPs.

I didn't flush my arp cache and I don't know how to do that.

*If I had to take a guess you have a system out their that scummed your Macs Ip Address

I think he means that you might have 2 computers with the same ip address on your network, which could create a lot of problems.

sorry about the edit i got interupted a few times and then remembered a few things

No, this is not the case and no problem with your editing.

Is it just one mac having the problem?

Yes, but the other Macs run Mac OS 9.2.2.

Have you tried setting up another user account to see if possibly one of the prefs files are corrupt?

Good idea. I should have already tried that as one of my first steps... will check it out on monday.

Just out of curiosity, is the "DNS Servers" field in your Network Settings on your OSX box set to the the IP address of your router/firewall? If not, I suggest you try putting your router/firewall IP address in the "DNS Servers" field. That might should solve your problem.

Just to keep you up to date:

Creating a new user didn't work.

I also tried the router as my DNS which didn't work at all.

My arp cache had only 2 entries. One obsolete which I flushed and a correct one for our linux router which I didn't flush. Should I?

Strange DNS lookup problems
 

I'm experiencing the same DNS problems on different MacOSX 10.3.3, but the same problem was on the previous releases (since 10.1).
When I'm trying to load one page in any browser, the first attempt fails while the second goes fine.
The problem appears only the first time I access one site. It seems as the timeout of the resolver is too short.
Watching with tcpdump I've found that the right IP is retrieved after 5 seconds, while the browser has already given the error.
If I retry to reload the page a second time there's no error since the IP is in the local DNS cache and the resolving process is a lot faster.

If I use a different Operating System on the same network there's no problem.

My local DNS is set to make recursive query starting from ROOT servers.
The file named.ca (containing addresses of root servers) is up to date.
I've tried also to set up a DNS which make query to our ISP provider, but the result is the same.

I'm looking for some settings to extend the timeout of the local resolver, but I didn't find any.
It seems there's not such option looking at "man resolver".

Have you, Olaf, resolved your problem?

Thanks!

No, I did a complete reinstall of my system and everything went fine again (frustrating).

Also, I think you have a different problem (beside the strangeness). If I remember correctly, my DNS queries went fast but wrong (host not found). So no timeout issue.

Maybe you have a general network issue. Are local network services running fine?

Good luck.

I've made some tests using tcpdump.

In the first I'm loading from a browser the page www.direzione.it on a host named skinner. The DNS (BIND 9.2.2) is on the server itchy and both are on the same domain pc.ibn. Both have Mac OS X 10.3.3.
From the browser I get the error. I think the problem is from the lookup request www.direzione.it.pc.ibn made just after 3 seconds, while the right resolution of www.direzione.it ended 4 seconds after the first request.

10:32:44.186194 IP skinner.pc.ibn.58526 > itchy.pc.ibn.domain: 23276+ A? www.direzione.it. (34)
10:32:44.891146 IP skinner.pc.ibn.58526 > itchy.pc.ibn.domain: 23276+ A? www.direzione.it. (34)
10:32:45.596308 IP skinner.pc.ibn.58526 > itchy.pc.ibn.domain: 23276+ A? www.direzione.it. (34)
10:32:46.301386 IP skinner.pc.ibn.58526 > itchy.pc.ibn.domain: 23276+ A? www.direzione.it. (34)
10:32:47.006632 IP skinner.pc.ibn.58527 > itchy.pc.ibn.domain: 60276+ A? www.direzione.it.pc.ibn. (41)
10:32:47.007236 IP itchy.pc.ibn.domain > skinner.pc.ibn.58527: 60276 NXDomain* 0/1/0 (88)
10:32:47.017220 IP skinner.pc.ibn.58528 > itchy.pc.ibn.domain: 26358+ A? www.direzione.it. (34)
10:32:47.722339 IP skinner.pc.ibn.58528 > itchy.pc.ibn.domain: 26358+ A? www.direzione.it. (34)
10:32:48.355875 IP itchy.pc.ibn.domain > skinner.pc.ibn.58526: 23276 2/2/0 CNAME direzione.it., A h217-220-37-123.albacom.net (122)
10:32:48.356118 IP itchy.pc.ibn.domain > skinner.pc.ibn.58526: 23276 2/2/0 CNAME direzione.it., A h217-220-37-123.albacom.net (122)
10:32:48.356252 IP itchy.pc.ibn.domain > skinner.pc.ibn.58526: 23276 2/2/0 CNAME direzione.it., A h217-220-37-123.albacom.net (122)
10:32:48.356351 IP itchy.pc.ibn.domain > skinner.pc.ibn.58526: 23276 2/2/0 CNAME direzione.it., A h217-220-37-123.albacom.net (122)
10:32:48.356513 IP itchy.pc.ibn.domain > skinner.pc.ibn.58528: 26358 2/2/0 CNAME direzione.it., A h217-220-37-123.albacom.net (122)
10:32:48.356841 IP itchy.pc.ibn.domain > skinner.pc.ibn.58528: 26358 2/2/0 CNAME direzione.it., A h217-220-37-123.albacom.net (122)
10:32:48.357326 IP skinner.pc.ibn.58529 > itchy.pc.ibn.domain: 55820+ AAAA? www.direzione.it. (34)
10:32:48.424937 IP itchy.pc.ibn.domain > skinner.pc.ibn.58529: 55820 1/1/0 CNAME direzione.it. (116)
10:33:04.762767 IP skinner.pc.ibn.58530 > itchy.pc.ibn.domain: 2815+ A? itchy.pc.ibn. (30)
10:33:04.763116 IP itchy.pc.ibn.domain > skinner.pc.ibn.58530: 2815* 1/3/2 A itchy.pc.ibn (136)
10:33:04.779614 IP skinner.pc.ibn.58531 > itchy.pc.ibn.domain: 13152+ AAAA? itchy.pc.ibn. (30)
10:33:04.779846 IP itchy.pc.ibn.domain > skinner.pc.ibn.58531: 13152* 0/1/0 (71)


In the second test I used a PC with Windows XP as the host client, xp-sistemisti. I load www.comune.trieste.it. The resolution lasted more than 6 seconds, but the page loaded correctly.

10:56:40.253811 IP xp-sistemisti.pc.ibn.optima-vnet > itchy.pc.ibn.domain: 52+ A? www.comune.trieste.it. (39)
10:56:41.247560 IP xp-sistemisti.pc.ibn.optima-vnet > itchy.pc.ibn.domain: 52+ A? www.comune.trieste.it. (39)
10:56:42.248373 IP xp-sistemisti.pc.ibn.optima-vnet > itchy.pc.ibn.domain: 52+ A? www.comune.trieste.it. (39)
10:56:44.251174 IP xp-sistemisti.pc.ibn.optima-vnet > itchy.pc.ibn.domain: 52+ A? www.comune.trieste.it. (39)
10:56:46.579730 IP itchy.pc.ibn.domain > xp-sistemisti.pc.ibn.optima-vnet: 52 1/2/0 A 195.120.252.3 (110)
10:56:46.579848 IP itchy.pc.ibn.domain > xp-sistemisti.pc.ibn.optima-vnet: 52 1/2/0 A 195.120.252.3 (110)
10:56:46.579936 IP itchy.pc.ibn.domain > xp-sistemisti.pc.ibn.optima-vnet: 52 1/2/0 A 195.120.252.3 (110)
10:56:46.580021 IP itchy.pc.ibn.domain > xp-sistemisti.pc.ibn.optima-vnet: 52 1/2/0 A 195.120.252.3 (110)
10:56:47.032921 IP xp-sistemisti.pc.ibn.optima-vnet > itchy.pc.ibn.domain: 53+ A? www.retecivica.trieste.it. (43)
10:56:48.025720 IP xp-sistemisti.pc.ibn.optima-vnet > itchy.pc.ibn.domain: 53+ A? www.retecivica.trieste.it. (43)
10:56:49.027109 IP xp-sistemisti.pc.ibn.optima-vnet > itchy.pc.ibn.domain: 53+ A? www.retecivica.trieste.it. (43)
10:56:49.122807 IP itchy.pc.ibn.domain > xp-sistemisti.pc.ibn.optima-vnet: 53 1/2/0 A server3-mediatechnologies.it.net (115)
10:56:49.122924 IP itchy.pc.ibn.domain > xp-sistemisti.pc.ibn.optima-vnet: 53 1/2/0 A server3-mediatechnologies.it.net (115)
10:56:49.123011 IP itchy.pc.ibn.domain > xp-sistemisti.pc.ibn.optima-vnet: 53 1/2/0 A server3-mediatechnologies.it.net (115)


If I use nslookup to make query from the command line of skinner (the mac host) the resolution is always correct.

This problem outlined above arises only if the resolution is a bit slow, more than 3 seconds I suppose. The DNS on itchy is configured to have recursion true and no forwarding.
Using our ISP DNS as forwarder, the problem seems to disappear just because most of lookup requests are faster than 3 seconds. But the problem still exists! I've made a lot of tries to find a domain not in the cache of our ISP DNS, but still the error is here.
The link is www.leo.ru. The DNS is on server luke.

10:51:31.167678 skinner.pc.ibn.58864 > luke.srv.ibn.domain: 60110+ A? www.leo.ru. (28)
10:51:31.872757 skinner.pc.ibn.58864 > luke.srv.ibn.domain: 60110+ A? www.leo.ru. (28)
10:51:32.577880 skinner.pc.ibn.58864 > luke.srv.ibn.domain: 60110+ A? www.leo.ru. (28)
10:51:33.283006 skinner.pc.ibn.58864 > luke.srv.ibn.domain: 60110+ A? www.leo.ru. (28)
10:51:33.988311 skinner.pc.ibn.58865 > luke.srv.ibn.domain: 42405+ A? www.leo.ru.pc.ibn. (35)
10:51:33.988882 luke.srv.ibn.domain > skinner.pc.ibn.58865: 42405 NXDomain* 0/1/0 (82) (DF)
10:51:33.997389 skinner.pc.ibn.58866 > luke.srv.ibn.domain: 51331+ A? www.leo.ru. (28)
10:51:34.702504 skinner.pc.ibn.58866 > luke.srv.ibn.domain: 51331+ A? www.leo.ru. (28)
10:51:35.407703 skinner.pc.ibn.58866 > luke.srv.ibn.domain: 51331+ A? www.leo.ru. (28)
10:51:36.112843 skinner.pc.ibn.58866 > luke.srv.ibn.domain: 51331+ A? www.leo.ru. (28)
10:51:36.818294 skinner.pc.ibn.58867 > luke.srv.ibn.domain: 64162+ A? www.leo.ru.pc.ibn. (35)
10:51:36.819250 luke.srv.ibn.domain > skinner.pc.ibn.58867: 64162 NXDomain* 0/1/0 (82) (DF)
10:51:36.819867 skinner.pc.ibn.58868 > luke.srv.ibn.domain: 27984+ AAAA? www.leo.ru. (28)
10:51:37.524977 skinner.pc.ibn.58868 > luke.srv.ibn.domain: 27984+ AAAA? www.leo.ru. (28)
10:51:38.230081 skinner.pc.ibn.58868 > luke.srv.ibn.domain: 27984+ AAAA? www.leo.ru. (28)
10:51:38.935210 skinner.pc.ibn.58868 > luke.srv.ibn.domain: 27984+ AAAA? www.leo.ru. (28)
10:51:39.640475 skinner.pc.ibn.58869 > luke.srv.ibn.domain: 11970+ AAAA? www.leo.ru.pc.ibn. (35)
10:51:39.641021 luke.srv.ibn.domain > skinner.pc.ibn.58869: 11970 NXDomain* 0/1/0 (82) (DF)
10:51:40.825388 luke.srv.ibn.domain > skinner.pc.ibn.58864: 60110 1/2/0 A master.chemforum.ru (108) (DF)
10:51:40.825555 luke.srv.ibn.domain > skinner.pc.ibn.58864: 60110 1/2/0 A master.chemforum.ru (108) (DF)
10:51:40.825700 luke.srv.ibn.domain > skinner.pc.ibn.58864: 60110 1/2/0 A master.chemforum.ru (108) (DF)
10:51:40.825911 luke.srv.ibn.domain > skinner.pc.ibn.58864: 60110 1/2/0 A master.chemforum.ru (108) (DF)
10:51:40.826052 luke.srv.ibn.domain > skinner.pc.ibn.58866: 51331 1/2/0 A master.chemforum.ru (108) (DF)
10:51:40.826186 luke.srv.ibn.domain > skinner.pc.ibn.58866: 51331 1/2/0 A master.chemforum.ru (108) (DF)
10:51:40.826318 luke.srv.ibn.domain > skinner.pc.ibn.58866: 51331 1/2/0 A master.chemforum.ru (108) (DF)
10:51:40.826506 luke.srv.ibn.domain > skinner.pc.ibn.58866: 51331 1/2/0 A master.chemforum.ru (108) (DF)

Is there any way to force the local resolver not to do the query with the local domain attached?
My /etc/resolv.conf now contains just:
nameserver 192.168.0.2

The DHCP server gave me the domain pc.ibn.
I dropped it from DHCP and the lookup queries to www.direzione.it.pc.ibn. disappeared, but if the process lasts more than 3 seconds the browser gives me an error.

Where can I set the resolver timeout?

Not much help I know, but I've got the same symptoms under X 10.3.2. I have a router/firewall built into my DSL modem, with DNS abilities and perhaps thats is causing extra delays? Regardless, its certainly very annoying!

I thought I had the problem licked when I lowered my MTU. At the time that I did this it seemed to help with pages timing out (some page items were not loading). Now if a page is not doing anything with a few seconds, I have to give it a hurry up.... a fix would most welcome!