Mail sent to a hosted domain does not arrive if third-party MX records are present

Overview Mail sent to a domain hosted by your account that uses third-party MX records does not arrive to the intended recipient. Mail is instead delivered locally to the server that hosts your domain. For example, if example.com uses Google Apps to handle e-mail, and mail originates from the same hosting server as in from a script, like a…

Separating mail to same user, different domain

Overview Accounts may host multiple domains under one account. In certain circumstances, an e-mail address on one domain must deliver to a different inbox than the same e-mail address on a different domain: info@mydomain.com must not deliver to the same inbox as info@myotherdomain.com Solution Each user within the control panel (Users > Manage Users) provides a…

Mail filtering

Overview Message filtering is done prior to delivery via maildrop. Each message goes through two levels of filters: (1) global — processed first in /etc/maildroprc followed by (2) local per-user filters in $HOME/.mailfilter. Basic filtering recipes are provided below. Syntax and usage may be found in mailfilter(7). Important: on older platforms, (less than v6), remember to…

Unable to send e-mail

Overview Client is able to receive e-mail, but not send. If client is unable to both send and receive e-mail, then refer to Accessing e-mail for proper login details. Note, this does not affect webmail. Only desktop/handheld mail clients apply. Causes Firewall restriction on port 25 ISPs commonly implement firewall blocks upstream on port 25…

POP3 vs IMAP e-mail protocols

Overview POP3 and IMAP are two separate protocols to access e-mail stored on the server. POP3 originated first in 1996 and IMAP in 2003. POP3 is designed for devices that have limited Internet connectivity and limited storage available on the mail server. POP3 is suitable for a dial-up connection or situations in which limited storage is available…

Improving mail filter performance

Overview E-mail that flows into the server goes through several phases of filtering before final delivery, including: DNSBL lookups on handshake Deep protocol inspection DomainKeys/SPF validation SpamAssassin filtering Whitelist management Hash-sharing systems (DCC & Razor) Token-based regex matching Markup filtering Bayesian filtering All steps in the filtering process are automated, except for Bayesian filtering that works by…

Accessing e-mail

Overview E-mail may be accessed either through webmail within the control panel or remotely from a desktop client such as Outlook, Thunderbird, or Mail. Important login information Your login will always be user@domain for e-mail. For example, if your domain is example.com and your username myadmin, then the proper e-mail login is myadmin@example.com and not myadmin. Your password is the same password…