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We have a WEB-server running around 12 ecommerce instances and having 4 IPS. 1 active, 3 just in case... One of our websites has been hacked recently and it was used for sending spam, what resulted in IP blacklisting.

What measures should be taken in order to correctly switch smtp to another IP?

Our exim4 folder contains the file domainips with all our domains+IP list. Should IPs be changed there.

Should we only change MX in DNS control panel?..

Which steps are obligatory for correct IP switch?

Configuration: exim4, dovecot, clamav, sa

Thank you very much.

Marco
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Tim White
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1 Answers1

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If your IP is now blacklisted it should not be used to send any good mail but it can continue to receive mails. Anyway you can change the IP address of the MX records of your domain as easy as change the IP addresses of their A record.

For example, if your MX records are

example.com.    IN    MX    10    mx1.mailserver.com.
example.com.    IN    MX    20   mx2.mailserver.com.

You can just change the A records of mx1.mailserver.com and/or mx2.mailserver.com.

The time needed for the propagation depends on the amount of the TTL setted on mx*.mailserver.com, but if your mailserver listens on both IP addresses during the migration you will be fine. After the migration (you can check with DNS lookups tools) you can just remove the old IP address from the mailserver listening.

Mat
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