Question How to set the "main" IP address when ipmanage doesn't do it?

[Bitpalast]

Upgrade vom Ony 17 to 17.5, CentOS 7.3 through GUI:

"Plesk pre-upgrade check
WARNING: Unable to find "main" IP address in psa database. Please, check Unable to list APS applications: Search results could not be loaded at the moment for more details."

MariaDB [psa]> select id, ip_address, main from IP_Addresses;
+----+----------------------+-------+
| id | ip_address           | main  |
+----+----------------------+-------+
|  1 | 88.99.123.123        | false |
|  2 | 2a01:4f8:111:1234::2 | false |
+----+----------------------+-------+
2 rows in set (0.00 sec)

But after "# /usr/local/psa/bin/ipmanage --reread" delivers "IP addresses were reread from the system." no changes are applied, both entries are still showing "false" in the "main" column.

On a test system that was recently upgraded the IPv4 address is checked as "main":

MariaDB [psa]> select id, ip_address, main from IP_Addresses;
+----+----------------------+-------+
| id | ip_address           | main  |
+----+----------------------+-------+
|  1 | 136.243.222.222       | true  |
|  2 | 2a01:4f8:2121:1234::2 | false |
+----+----------------------+-------+
2 rows in set (0.00 sec)

My question is: Why isn't ipmanage setting the main IP address and can I alter the "main" column in the IP_Addresses table to set the IPv4 address to "true" or are there other implications that need to be watched, too? What exactly is the meaning (the effect) of a "main" IP address and why is the host system running without trouble so far despite there is no "main" IP address set?

 

[Bitpalast]

I have now altered the flag by

UPDATE IP_Addresses SET main='true' WHERE ip_address LIKE '88.99.123.123';

and it seems to change nothing in Plesk but that now the IP address is displayed in bold face on Tools & Settings > IP Addresses. According to documentation, the difference for a "main" IP address is, that a "main" IP address cannot be removed. We'll see if issues occur due to the update.