I have an issue whereby clients are unable to connect to Courier Imap
with the error that there are too many connections from their IP. I have
changed the following parameter as follows:
in the imapd file. I restarted courier imap, but still the same problem.
That's the maximum total number of connections. There's also a different
setting for the maximum number of connections from the same IP address,
which may or may not apply to you.