Postfix SMTP

From Wiki

(Difference between revisions)
Jump to: navigation, search
Line 36: Line 36:
  //If there are entries already - thats fine, just comment delimit them.
  //If there are entries already - thats fine, just comment delimit them.
The sender is then bounced back an email saying "Blocked by spamhouse" and it is their, or their ISP's responsibility to remove themselves from spamhaus.<br>
The sender is then bounced back an email saying "Blocked by spamhouse" and it is their, or their ISP's responsibility to remove themselves from spamhaus.<br>
-
Note: "ping sbl-xbl.spamhaus.org" wont resolve. What postfix does when checking an ip (e.g. w.x.y.z), is to "ping z.y.x.w.sbl-xbl.spamhaus.org", and if that resolves - that ip is listed as spam. (thanks davisc).  
+
'''Note:''' "ping sbl-xbl.spamhaus.org" wont resolve. What postfix does when checking an ip (e.g. w.x.y.z), is to "ping z.y.x.w.sbl-xbl.spamhaus.org", and if that resolves - that ip is listed as spam. (thanks davisc). <br>
-
Note: Make sure ICMP packets are allowed through the firewall. Otherwise postfix will get a "Destination Not Reachable" and allow the mail through.<br>
+
'''Note:''' Make sure ICMP packets are allowed through the firewall. Otherwise postfix will get a "Destination Not Reachable" and allow the mail through.<br>
See more details at: http://jimsun.linxnet.com/misc/postfix-anti-UCE.txt  and http://www.redhat.com/support/resources/howto/RH-postfix-HOWTO/x441.html
See more details at: http://jimsun.linxnet.com/misc/postfix-anti-UCE.txt  and http://www.redhat.com/support/resources/howto/RH-postfix-HOWTO/x441.html

Revision as of 09:03, 30 January 2007

Contents

Install as per normal

apt-get install postfix
Choose Internet Site Config.

After Install - Main folder = /etc/postfix
Main file = main.cf

Basic Changes:

Just the name used to identify server
myhostname = mail.domain.com
//disable lookup of usernames disable_vrfy_command = yes Remove hash beside delay_warning_time = 4h

Advanced Changes:

To prevent cross over emails between multiple domains,

e.g. where root@mydomain1.net and root@mydomain2.net are on the same server.

Add the following line into /etc/postfix/main.cf:
smtpd_sender_restrictions = check_recipient_access hash:/etc/postfix/restrict
Create the file: /etc/postfix/restrict
goodemail@mydomain2.net     OK
mydomain2.net               REJECT

To activate/ add this file into postfix, type in the shell ->
postmap /etc/postfix/restrict

Further Details at: http://www.seifried.org/security/index.php/Closet20001122_Postfix_-_The_Sendmail_Replacement,_Part_II

Restrict Mail delivery to Local users

On a lists (mailman) server I run - I want to disable mail delivery to local users, however I still want Postfix to deliver mail to /etc/aliases. The line below, which is to be put into /etc/postfix/main.cf forces postfix to only consult $alias_maps (which is: hash:/etc/aliases ).

local_recipient_maps = $alias_maps

Blocking Spam with spamhaus and Postfix

This is commonly referred to as a "Postfix anti-UCE configuration" (UCE - unsolicited emails). Postfix, with a very simply modification can block incoming email via spamhaus RBLs (Real Time Black-Hole Lists). The following line is to be added to /etc/postfix/main.cf:

smtpd_sender_restrictions reject_rbl_client sbl-xbl.spamhaus.org, reject_rbl_client bl.spamcop.net
//If there are entries already - thats fine, just comment delimit them.

The sender is then bounced back an email saying "Blocked by spamhouse" and it is their, or their ISP's responsibility to remove themselves from spamhaus.
Note: "ping sbl-xbl.spamhaus.org" wont resolve. What postfix does when checking an ip (e.g. w.x.y.z), is to "ping z.y.x.w.sbl-xbl.spamhaus.org", and if that resolves - that ip is listed as spam. (thanks davisc).
Note: Make sure ICMP packets are allowed through the firewall. Otherwise postfix will get a "Destination Not Reachable" and allow the mail through.
See more details at: http://jimsun.linxnet.com/misc/postfix-anti-UCE.txt and http://www.redhat.com/support/resources/howto/RH-postfix-HOWTO/x441.html

Debugging and Testing via Telnet

SENDING AN EMAIL VIA TELNET 25 & Testing forwarding

mail from: sri@mara.net
rcpt to: user@lastre.com
data
.
quit

Test and get working Normal - Should be able to send and revieve via pine etc.

Had to adjust /etc/hosts with domain name (this allowed sending emails ok):

127.0.0.1       localhost
136.201.1.250   kartbuilding.net        phidebian

Good URLS

http://www.muine.org/~hoang/postfix.html

http://www.debianhelp.co.uk/postfix.htm


Managing Postfix

Delete an Email from the Queue

For Example - sending an email to someone and it bounces. Defauly retry is for 3 days. To remove it manually :

postsuper -d queue_id

Tons more info at: http://www.postfix.org/postsuper.1.html

Personal tools