Sorbs is a infamous DNS blacklist born to try to fight spam. They have a too much restrictive policy that won’t block spam at all but they just create some pain to your MTA.
They can delist your IP a couple of times but if one of your clients get hacked your good quality MTA will be listed for months, even years!
What they don’t understand is that we work with our IP reputation, so just change the IP is not a valid solution. When a valid MTA got abused to send spam the problem is generally solved in hours, or even minutes. A one month list will generate a great problem to the hacked MTA’s clients.
The only solution is: DON’T USE SORBS AT ALL. The list is not business oriented and so is only valid for lamers, bofh sysadmins and nerds…. ok I’m a bofh, nerd sysadmin but I don’t use Sorbs anymore. Sorry.
NOTA: Tell your sysadmins to NOT USE SORBS.