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Postfix log shows lots of these:

warning: hostname client.lab.lan does not resolve to address 192.168.1.153

Yet a DNS lookup from the server shows that it does resolve:

# nslookup client.lab.lan
Server:         192.168.10.242
Address:        192.168.10.242#53

Name:   client.lab.lan
Address: 192.168.1.153
Name:   client.lab.lan
Address: 192.168.10.4

I'm assuming it has something to do with the multiple A records, but no idea how to fix it.

Any hints on how to just disable that warning would be appreciated too.

Jochen
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  • Are you not the administrator of the DNS server? The way to fix multiple records is to remove the extraneous records. – gparent Jul 25 '13 at 14:32
  • There are no extraneous records. As far as I know, having multiple A records is perfectly valid. – Jochen Jul 26 '13 at 01:46

1 Answers1

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The fact that there are multiple A records means that you have a roughly 50% chance of getting one or the other. You can either (a) remove one of the A records or (b) create the appropriate PTR records so that both addresses reverse to the correct value.

larsks
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  • I have valid PTR records for both A records. Those would only affect revers lookups though wouldn't they? Postfix appears to be complaining about a forward lookup. – Jochen Jul 26 '13 at 01:47
  • Possibly, given an ip address, it (a) first does a reverse lookup on that to get a hostname and then (b) does a forward lookup on that to see if it matches the ip address used in (a). – larsks Jul 26 '13 at 01:50