Outgoing Spam Restrictions

So as to protect our mail servers from block lists and to protect potential spam or malware being relayed on, we have a number of checks that are applied to email being sent through smtp.aa.net.uk. These include:

• IPs not on our network will need to Authenticate using their mailbox credentials
• We'll block individual messages if they are bounces (mail delivery failure notifications) - we don't like to relay on bounce messages from customers own mail servers
• IP addresses on Spamhaus's CSS or XBL block lists may be denied access
• We'll block individual messages if they contain malware (virus)
• We'll block individual messages if the sender address is invalid (e.g. no MX records etc.)
• We'll block Authenticated users or IPs if they send multiple emails in a short time period to invalid email addresses
• We'll block Authenticated users or IPs if they try to send multiple emails in a short time period that have a high high spam score

There are other check, but the ones above are the main ones.