Most common Email Transfer Agents (MTA) for web servers
Mail transfer from server are done through varous Mail Transfer Agents only. You will see an overview and their related functionality in below article.
There are some technuiqe/tools to deliver email from server . Most commons email tranfer agents are
*. Exim: This is a mail tranfer agent (MTA) that is freely distributed under GPL licence.Exim4 is currently default MTA under debian/linux systems. In terms of performance exim has been usually deployed in busy environment where large number of emails to be delivered immediately without queuing however its queue based performance is not at part if queue is large. So from that perspective its only suited for low traffic websites not on high traffic websites.
*. SendMail: Sendmail is general purpose MTA which support many kinds of mail delivery and mail transfer methods including SMTP, ESMTP, DECnet’s Mail-11, HylaFax, QuickPage and UUCP.Sendmail was acquired by Proofpoint, Inc on 1 October 2013.
Send mail through command line using sendmail
To check if sendmail is configured on server or not (run below code on command line)
sendmail [email protected]
it should send an email
*. Postfix: Postfix is free open source MTA which routes and delivers e-mails. It was created as an alternative of sendmail MTA. In terms of performance Postfix can deliver 300 message delivery per second or more than that based on server to server. This MTA does very good even in case of large queue of emails transfer.
How to debug if mails are being send from server or not from command line on Linux:
linux command to check maillog on Linux machine
tail -20 maillog
It will show last 20 mails logs
Apr 2 11:16:02 sd-57605 postfix/cleanup: 5DB7B501690: message-id=<201404 [email protected]>
Apr 2 11:16:02 sd-57605 postfix/qmgr: 5DB7B501690: from=<[email protected]>, size=3329, nrcpt=1 (queue active)
Apr 2 11:16:05 sd-57605 postfix/smtp: 5DB7B501690: to=<[email protected] >, relay=mx-indiabiz.mail.gm0.yahoodns.net[188.8.131.52]:25, delay=2. 7, delays=0.01/0/0.82/1.9, dsn=2.0.0, status=sent (250 ok dirdel)
Apr 2 11:16:05 sd-57605 postfix/qmgr: 5DB7B501690: removed
Apr 2 13:35:58 sd-57605 postfix/pickup: D2655501690: uid=48 from=<apache >