Starting 4PM on June 11th, 2008 we have began enforcing anti-hammering policy on all of our mail servers. This policy is aimed to protect our users from denial of service attacks, brute force password scanning, and poorly configured mail clients.

We have placed a hard limit on the number of connections we allow to originate from one IP address in a unit of time as follows:

Maximum allowed number of POP3 connections per minute per IP: 10
Maximum allowed number of IMAP4 connections per minute per IP: 10

Excceding this rate of connections will place your IP address in to a block list for a 15 minute cool-down. After the 15 minute cool-down period has passed, you may resume connections to our mail server as long as you do not exceed anti-hammering limits againg. This policy should not affect normal usage unless you have configured your POP3/IMAP client to check messages every 6 seconds. We suggest setup POP3 new mail frequency to once every 5 minutes and no more than once every 1 minute.