Odd problem with DNS and IP change.

[Tim Judd]

On Sat, Feb 28, 2009 at 4:30 PM, Derek Ragona <
derek at computinginnovations.com> wrote:

> At 09:40 AM 2/28/2009, Andrei Brezan wrote:
>
>> Hello list,
>>
>>        I have a strange problem and I don't know what to relate it to. My
>> ISP
>> changed my IP from (eg) 10.1.1.1 to 15.1.1.1. I have changed my zone
>> files to reflect that change.
>>
>> "dig -t mx domain.com" results in mail.domain.com 3600 IN A 15.1.1.1
>> (the new ip). However when i try:
>>
>> "ping mail.domain.com" it tries to get to 10.1.1.1 the old ip and gets
>> time to live exceeded fro an ip along the route. When i try to ping
>> domain.com it gets all ok as it pings the new ip. I've also tried dig
>> @(forwarders in named.conf) and they to got the correct mx dns entry for
>> domain.com.
>>        In rc.conf i have hostname="mail.domain.com" (eg), i haven't
>> changed
>> it, i'm thinking it's something related to hostid or hostuid but i don't
>> know where to search for this topic.
>>        If anyone has a clue what to try or where to look upon this
>> behavior
>> please shed some light.
>>
>> Thank you.
>>
>>
> Check /etc/hosts which is used before DNS.
>
>        -Derek
>

Depends on your nsswitch.conf(5) setup.  If dns is specified before files,
DNS will be checked before /etc/hosts will be.

It's all configurable and it's important to know the difference