This will be the goto to help solve e-mail delivery issues and talk about many practical issues that happen between developers, admins and scripts that send e-mail and do things that may not be acceptable or cause deliverability problems. Sendmail Stuff Edit /etc/mail/sendmail.mc The problem is that if you send directly out from the server using the mail function, the Return-path of the e-mails will be username@thehostnameoftheserver.com. Let........

systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system. The key commands or arguments you will use with systemctl are the following: Unit Commands: list-units [PATTERN...] List loaded units &nbs........

yum -y install fail2ban vi /etc/fail2ban/jail.conf [asterisk-tcp] enabled = true filter = asterisk action = iptables-multiport[name=asterisk-tcp, port="5060,5061", protocol=tcp] sendmail-whois[name=Asterisk, dest=you@example.com, sender=fail2ban@example.com] logpath = /var/log/asterisk/messages maxret........

relay=alt4.gmail-smtp-in.l.google.com. [74.125.136.26], dsn=4.0.0, stat=Deferred: 421-4.7.0 [ 10] Our system has detected an unusual rate of This is strange because the mail server IP is not blacklisted anywhere and the IP itself has not been used for years and this server is clean and has only sent a few e-mails to gmail.com in its entire time. I wonder if this is a legacy block on a whole range of IPs as punishment for others in the block........

pxe-32 tftp open timeout The solution was to enable tftp in xinetd with "chkconfig tftp on". See the troubleshooting below: chkconfig --list NetworkManager 0:off 1:off 2:off 3:off 4:off 5:off 6:off acpid 0:off&n........

Jul 11 15:20:58 tor sendmail[9617]: r6AKjOD07: to= mailserver.com was the hostname of the server, sendmail sends this by default and many mailservers will reject mail to a hostname that does not resolve or exist. The easiest way is just to change the hostname and make sure it does resolve to something. I read there is a way in sendmail.mc to manually set a hostname but I never got it working: vi /etc/mail/sendmail.mc define(`confDOMAIN........

Step #1 - Create Wrapper Script vi /usr/local/bin/phpsendmail #!/usr/bin/php ........

Centos 5 Postfix and SPAMASSASSIN Tutorial yum install spamassassin chkconfig spamassassin on vi /etc/mail/spamassassin/local.cf ############## #required_hits 5 #report_safe 0 #rewrite_header Subject [SPAM] #5 is the least restrictive (means only the most obvious SPAM is caught. 0 is obviously the most restrictive/sensitive and would have lots of false positives require........

understanding /etc/aliases *remember to apply changes you need to run "newaliases" after editing /etc/aliases one thing I don't get is that it doesn't allow you to specify the whole e-mail address on the left-hand side eg: yourfullemail@domain.com: someotheremail@domain.com postalias: warning: /etc/aliases, line 109: name must be local (if you try the above) It works more like this: your........

I wasted a lot of time wondering why I could never find those packages. Check the /etc/yum.conf file and at the bottom look for the "exclude=" line. Below is what I found in mine exclude=apache* httpd* mod_* mysql* MySQL* da_* *ftp* exim* sendmail* php* bind-chroot* Just remove those entries or uncomment that line and you'll get access to the missing applications.........

PHP cannot access /usr/bin/opensslI have verified the username that runs the process is able to access /usr/bin/openssl and it does exist but the PHP script is saying it doesn't exist: [code:1:1fd0f3abbe] if (!file_exists($OPENSSL)) { //echo "ERROR: OPENSSL $OPENSSL not foundn"; }[/code:1:1fd0f3abbe] I don't get itI can clearly see the contents of /usr/bin by using the PHP system fu........