Server Management: IP Mapping Guideline - Plesk

Server Management: IP Mapping Guideline

When you migrate domains from one server to another, you’ll need to configure them so that they use the destination server’s IP addresses. This process is known as IP mapping, and it’s something that can be done either manually or automatically. For best results you’ll want to have a shared IP address on the server you’re migrating to for each shared IP address on the server you’re migrating from, and the same goes for dedicated IP addresses, too. When the migration is all done, go through the IP addresses that the Migrator assigned and re-assign any that might need attention.

Automatic IP Mapping

The IP mapping process is normally something that happens without the need for any user input, as part of the migration. Plesk Migrator tries to re-allocate the domains being moved to the IP addresses on the destination server in line with these rules:

  • A dedicated IP address that has not been allocated will be assigned to domains that were given a dedicated IP address on the source server, where possible. If not (perhaps because there aren’t any unallocated dedicated IP addresses left on the destination server), the default shared IP address will be used instead.
  • Plesk Migrator will try to assign domains that used the same shared IP address on the source server to a different shared IP address on the destination server, where at all possible. If this can’t be achieved (say, because there aren’t as many shared IP addresses on the destination server as there are on the source server), the default shared IP address will be used instead.

Alternatively, the IP mapping file or the migration list file can be used to go through the IP mapping process manually.

Note: different mapping methods can be combined. For instance, you can use the migration list to stipulate common mapping rules, and then specify particular addresses for certain domains using the mapping file.

Using the Mapping File for IP Mapping

The IP mapping is a plain text file that consists of a pair of columns of IP addresses separated by the whitespace character. Those in the left column are the ones on the server you’re migrating from. They get matched to the ones in the right-hand column, which are the corresponding IP addresses from the server you’re migrating to. The IP mapping file should only contain the IP addresses and no other information—not even comments—should be added to it. Blank lines are permitted though.

Here’s an example of the contents in an IP mapping file:

192.168.1.11 11.53.1.16

192.168.1.12 11.53.1.17

192.168.1.12 11.53.1.17

In this illustration, domains that use the IP address 192.168.1.11 get the IP address 11.53.1.16. Those with the IP addresses 192.168.1.12 and 192.168.1.12, get the IP address 11.53.1.17.

Once the mapping file has been prepared, you can give it to the Plesk Migrator by using this option:

--ip-mapping-file IP_MAPPING_FILE

where IP_MAPPING_FILE is the path to the mapping file (either relative or absolute to the current working directory).

IP Mapping Using the Migration List File

This way of doing IP mapping may be more complex but it gives you greater control over assigning IP addresses. When the file is ready you can edit it, referring to the samples below for reference:

IPv4: 11.53.1.16
domain1.tld
domain2.tld
IPv4: 11.53.1.17
domain3.tld

Here, domains domain1.tld and domain2.tld will be given the IP address 11.53.1.16. Domain domain3.tld will get the IP address 11.53.1.17.

IPv4: shared
domain1.tld
domain2.tld

Here, both domains are assigned a shared IP address.

IPv4: dedicated
domain1.tld
domain2.tld

With this one, each domain gets a randomly chosen dedicated IP address (there have to be no fewer than two unallocated dedicated IP addresses on the server being migrated to).

IPv4: auto
domain1.tld
domain2.tld

Here, each domain gets an IP address in accordance with the automatic IP mapping rules.

IPv6: none
domain1.tld
domain2.tld

In this instance, neither domain gets an IPv6 address, but IPv4 addresses can still be assigned (as a domain can’t be created without an IP address).

IPv4 and IPv6 IP addresses can be assigned to domains using the migration list file. Any domain can receive an IPv4 address, an IPv6 address, or both. When stipulating which IP address will be assigned to a domain, you can either use a particular address or use the placeholders— shared/dedicated/auto/none.

IPv4: 11.53.1.16
IPv6: 2002:5bcc:18fd:d:904c:9277:339a:ce56
domain1.tld

In this case, the domain will be given both the IPv4 and the IPv6 addresses.

When resellers receive IP addresses these are circulated to all domains used for customer accounts as well as the reseller’s own domains.

Reseller: res1
IPv4: 11.53.1.16
domain1.tld
Customer: cust1
domain2.tld
Reseller: res2
domain3.tld

In this case, domains domain1.tld and domain2.tld will get the IP address 11.53.1.16, and the IP address for the domain domain3.tld will be set in accordance with the automatic IP mapping rules.

Note: When manually assigning an IP address to a reseller, the IP address must either be free or one that’s already included in the reseller’s IP pool. With automatic IP mapping, only free IP addresses will be given to resellers.

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