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DNS madness on Woody



Hi

I have asked about this before but am still not sure exactly what is going on 
or how to fix it except apparently its something to do with IPv6.

My PC is having weird DNS issues. I can pick a host on the internet and ping 
it OK from the command line but my MTA (postfix) cannot resolve it. Another 
weird thing is that I can add an address to the hosts file and ping will use 
the address from the hosts file but postfix will ignore the entry in the 
hosts file and use a DNS lookup instead. This means I cannot mail people in 
our other offices as the mailserver will only accept SMTP mail from the 
internet and our DNS returns the internal address of the server (ie via the 
internal LAN).

Here is an example of the postfix issue to a real host on the internet and all 
my DNS releated config.

One thing springs to mind, can I disable the IPv6 functionality without 
recompiling my kernel ?

Thanks

Pat

mail.log

Jul 15 11:48:01 dasterdly postfix/smtp[22546]: 87E40114056: 
to=<oldtools@clamor.law.cornell.edu>, relay=none, delay=1222, status=deferred 
(Name service error for clamor.law.cornell.edu: Host not found, try again)

But ping works:-

dasterdly:/etc# ping clamor.law.cornell.edu
PING clamor.law.cornell.edu (128.253.22.219): 56 data bytes
64 bytes from 128.253.22.219: icmp_seq=0 ttl=231 time=218.8 ms
64 bytes from 128.253.22.219: icmp_seq=1 ttl=231 time=195.2 ms

And telnet on port 25:-

dasterdly:/etc# telnet clamor.law.cornell.edu 25
Trying 128.253.22.219...
Connected to clamor.law.cornell.edu.
Escape character is '^]'.
220 clamor.law.cornell.edu ESMTP Lyris ListManager service ready
^]

Here is ping to a mailserver in our other office

dasterdly:/etc# ping azlan.com
PING azlan (193.129.67.7): 56 data bytes

But the postfix gives this, note the incorrect IP address !

Jul 15 12:07:18 dasterdly postfix/smtp[22613]: 00AE41140C4: 
to=<pcolbeck@azlan.com>, relay=azlan.com[10.44.5.133], delay=1, 
status=bounced (host azlan.com[10.44.5.133] said: 550 5.7.1 Unable to relay 
for pcolbeck@azlan.com).

Here is my hosts file etc:

dasterdly:/etc# cat /etc/hosts
127.0.0.1       dasterdly       localhost localhost.esc.azlan.co.uk
10.44.70.8      dasterdly       dasterdly.esc.azlan.co.uk
10.44.69.115    mail            mail.esc.azlan.co.uk
193.129.67.7    azlan           azlan.com


# The following lines are desirable for IPv6 capable hosts
# (added automatically by netbase upgrade)

::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

dasterdly:/etc# cat /etc/resolv.conf
order hosts bind
domain esc.azlan.co.uk
nameserver 10.44.69.102
nameserver 10.44.65.120

dasterdly:/etc# cat nsswitch.conf
# /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc' and `info' packages installed, try:
# `info libc "Name Service Switch"' for information about this file.

passwd:         compat
group:          compat
shadow:         compat

hosts:          files dns
networks:       files

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

netgroup:       nis






-- 
-----------------------------------
Pat Colbeck
E-mail:	pcolbeck@bashq.org
Tel:	I'm not telling
-----------------------------------


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