hostname problem

lukesc · 08-06-2009, 06:27 PM

On our network we have a primary router that connects us to the internet and an exchange server w/ a static ip address that provides DCHP for our network (it also provides a windows domain network for win boxes).

We then have a second router setup as a wireless access point (bypassing the router) and a web server connected to that with a host name of "dev.local".

Windows machines connected to the network are logged onto the windows domain through "computername.company.local" and other non-windows boxes just connect through the network using the DCHP.

When I connect to the web server through its IP Address everything loads almost instantly like it should. But when I connect to the web server using "dev.local" (http://dev.local) it takes 20-45 seconds for a page with a few images to load.

I've tried doing a traceroute and ping the server and the speed and result of doing these things are exactly the same when doing it to the ip address or hostname. Yet when I connect to the web server there is a noticeable speed difference. I can't seem to explain why connecting to dev.local is any different than connecting to the IP Address. The only difference is I'm going through the exchange server's DNS to locate dev.local. But other types of connections don't seem to be effected.

Anyone got any idea of what's causing this?

jschiwal · 08-06-2009, 07:12 PM

Names that have .local at the end may be using zeroconf (avahi on linux) to resolve the address. It is notoriously slow.
Could you post your /etc/resolv.conf and /etc/nsswitch.conf files? Also post "ps -e | grep avahi".

This link might explain what is happening: http://www.mail-archive.com/debian-b...msg271167.html

Another possibility is the delay is due to nss_mdns6. This will cause long delays. You need to explicitly indicate mdns4 or mdns4_minimal (instead of mdns or mdns_minimal) in /etc/resolve.conf to avoid delays.

from http://0pointer.de/lennart/projects/nss-mdns/ :

Code:

# /etc/nsswitch.conf

passwd:         compat
group:          compat
shadow:         compat

hosts:          files mdns4_minimal [NOTFOUND=return] dns mdns4
networks:       files

protocols:      db files
services:       db files
ethers:         db files
rpc:            db files

netgroup:       nis

If the MS DNS server will serve an address for dev.local, then you could remove the mdns entries from /etc/nsswitch.conf.

For my home network, I mapped static IP address to the mac addresses (using a linksys wireless router) so the DHCP server would issue the same addresses. This allowed me to add the host names to /etc/hosts without worrying about the IP addresses changing on my. I have them configured to get their address from DHCP. This gives me the best of both worlds.

lukesc · 08-06-2009, 07:28 PM

/etc/resolv.conf is:

Code:

; generated by /sbin/dhclient-script
search company.local
nameserver 10.1.10.254

The IP address 10.1.10.254 goes to the exchange/dchp server for the lan.

/etc/nsswitch.conf is (without comments):

Code:

passwd: files
shadow: files
group: files

hosts: files dns

bootparams: nisplus [NOTFOUND=return] files

ethers: files
netmasks: files
networks: files
protocols: files
rpc: files
services: files

netgroup: nisplus

publickey: nisplus

automount: files nisplus
aliases: files nisplus

"ps -e | grep avahi" reads:

Code:

2856 ? 00:00:00 avahi-daemon
2857 ? 00:00:00 avahi-daemon

lukesc · 08-07-2009, 02:18 PM

We have a local DNS server for the network and I just created my own local-only TLD. The new hostnames do not have the same problem.

jschiwal · 08-08-2009, 10:20 AM

I don't think I paid close enough attention to

Quote:

I've tried doing a traceroute and ping the server and the speed and result of doing these things are exactly the same when doing it to the ip address or hostname.

If you run "getent hosts dev.local" and "host dev.local", is there a delay. Maybe the problem isn't in name lookup for dev.local. Could it be the other way around?

Does the server or it's firewall do reverse lookups for the logs?

lukesc · 08-11-2009, 11:28 AM

Quote:

Originally Posted by jschiwal

I don't think I paid close enough attention to

If you run "getent hosts dev.local" and "host dev.local", is there a delay. Maybe the problem isn't in name lookup for dev.local. Could it be the other way around?

Does the server or it's firewall do reverse lookups for the logs?

I don't think dev.local even works on itself. In order to get it to resolve I had to add it to /etc/hosts.

Is this the issue?