Thank you for the advice Thomas.

Could anyone give me an idea as to the maximum number of local users a single Mercury server could provide for?

Obviously this would depend on how much mail each of them was sending & receiving, and how many simultaneous pop/imap connections the server had to deal with. But, in addition to those issues, the users are held in PMAIL.USR. A database reading user details from a table would have indexing to quickly locate a given record. PMAIL.USR is just a text file. Can Mercury still operate well if that contained say one or two thousand users?

Regards

Richard

Could anyone give me an idea as to the maximum number of local users a single Mercury server could provide for?

A few thousand POP3/SMTP users will be no problem at all, most any server equipment should be able to handle that number.  IMAP4 is a different story since the users generally stay connected pretty much 24/7 and use multiple devices to make connections to the host.  Unless you have a honkin'  huge server with multiple processors and almost unlimited RAM I would suspect that the users need to be limited to a few hundred.  YMMV