== SMTP Restrictions ==
Our upstream providers have placed restrictions on their SMTP servers in order to prevent abuse. These limits are as follows:

=== Limitations in place on smtp-is.zsd.co.za and smtp-za.zsd.co.za ===
'''Policy:'''

 * The end user can only send to a maximum of 100 recipients per mail message, this includes To:, Cc: and Bcc:.
 * The size limitation is 102.4 Mega Bytes per message.
 * Relaying is only allowed from IS DSL ip ranges.
 * The sender and recipient domains must be a Fully Qualified Domain Name and be a valid resolvable DNS domain.
 * No sender From: addresses from free mail services, i.e. Yahoo, Hotmail, GMail, etc are accepted.
 * Testing for open relays on the IS DSL user ip space and blocking access to these abusers.
 * Blacklisting and block ip's identifying themselves as one of the smtp servers.
 * Blacklist ip's sending mail to known spam traps for a minimum of 1 hour.
 * Manual process of blacklisting domains and/or sender addresses due to abuse complaints being logged.
 * Rate limiting incoming mail from client connections to 50 recipients max per minute.
 * Rate limiting incoming connections from client connections to 7 per unique ip on each server.
 * Reject any mail that has more than 50 MIME parts.
 * Reject any mail considered to be malware infected.
 * Reject any mail looking like spam.

'''Technicial Policy:'''

 * Max recipients in a single connection - 100
 * Max mail size including the encoding of the mail - 100MB
 * 7 Concurrent connections per server. Total concurrent connections -> 28

=== Limitations in place on smtp-sx.zsd.co.za ===
 * 25 recipients per message
 * 250 MB traffic per hour
 * 300 recipients per hour
 * 1000 recipients per 24 hours
 * Users are not allowed to send to 3 or more AOL, Yahoo or Hotmail email accounts in the same email.

[[attachment:SYNAQ_Securemail_Technical_Requirements_and_System_Limits.pdf|Hosted Exchange policy document]]