This post will show how to install sendmail smtp service on CentOS 6.5. By default only postfix smtp service included in CentOS 6.5. Due to some reasons you will to run sendmail service instead of postfix. But the purpose of both services still the same providing SMTP email transport service and running as an email relay on your linux system.
1. Install sendmail :
[root@centos6.5 ~]# yum install sendmail -y .. .. .. .. Setting up Install Process Resolving Dependencies --> Running transaction check ---> Package sendmail.x86_64 0:8.14.4-8.el6 will be installed --> Processing Dependency: procmail for package: sendmail-8.14.4-8.el6.x86_64 --> Processing Dependency: libhesiod.so.0()(64bit) for package: sendmail-8.14.4-8.el6.x86_64 --> Running transaction check ---> Package hesiod.x86_64 0:3.1.0-19.el6 will be installed ---> Package procmail.x86_64 0:3.22-25.1.el6 will be installed --> Finished Dependency Resolution Dependencies Resolved ==================================================================================================== Package Arch Version Repository Size ==================================================================================================== Installing: sendmail x86_64 8.14.4-8.el6 base 717 k Installing for dependencies: hesiod x86_64 3.1.0-19.el6 base 20 k procmail x86_64 3.22-25.1.el6 base 163 k Transaction Summary ==================================================================================================== Install 3 Package(s) Total download size: 900 k Installed size: 1.9 M Downloading Packages: (1/3): hesiod-3.1.0-19.el6.x86_64.rpm | 20 kB 00:00 (2/3): procmail-3.22-25.1.el6.x86_64.rpm | 163 kB 00:00 (3/3): sendmail-8.14.4-8.el6.x86_64.rpm | 717 kB 00:06 ---------------------------------------------------------------------------------------------------- Total 117 kB/s | 900 kB 00:07 Running rpm_check_debug Running Transaction Test Transaction Test Succeeded Running Transaction Installing : procmail-3.22-25.1.el6.x86_64 1/3 Installing : hesiod-3.1.0-19.el6.x86_64 2/3 Installing : sendmail-8.14.4-8.el6.x86_64 3/3 Verifying : hesiod-3.1.0-19.el6.x86_64 1/3 Verifying : procmail-3.22-25.1.el6.x86_64 2/3 Verifying : sendmail-8.14.4-8.el6.x86_64 3/3 Installed: sendmail.x86_64 0:8.14.4-8.el6 Dependency Installed: hesiod.x86_64 0:3.1.0-19.el6 procmail.x86_64 0:3.22-25.1.el6 Complete!
2. Start Sendmail service :
[root@centos6.5 ~]# service sendmail start Starting sendmail: [ OK ] Starting sm-client: [ OK ]
3. Test sendmail respond on port 25 :
[root@centos6.5 ~]# telnet localhost 25 Trying ::1... telnet: connect to address ::1: Connection refused Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 centos6.5.ehowstuff.local ESMTP Sendmail 8.14.4/8.14.4; Sun, 10 Aug 2014 20:48:52 +0800
Sendmail is a general purpose internetwork email routing facility that supports many kinds of mail-transfer and -delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet. In certain cases, you has to stop and remove the sendmail service on your server. It could be you want to install other smtp service such as postfix. In order to make postfix smoothly running, sendmail should be stop and removed. This post will show you on how to stop and remove sendmail on linux Fedora 16 server.