I have an old Exim4U installation that has been serving me well for the past few years.

Recently we got on spamlists frequently. We can tell all the time what happened (weak passwords), but delisting is hard and slow, thus I would need to be able to set another IP address temporarily for outgoing mail. With this I can solve the problem temporarily, wait for the original IP to get delisted and then set it back.

How can I achieve this the easiest way? I have another IP already on eth1 configured with another hostname and reverse also.