Linux Admin Zone

When we decided to host our mail with some other provider, the question of configuring our web servers to use that provider to send mail arise. Having CentOS and postfix as mail service in our hosts, we followed these steps to tell local postfix to use other smtp service to send mails.

1. Suppose you have example.com domain, create one separate mail account to be used in your scripts residing on web server for sending mails. As an example, let’s assume we have mailer@example.com with password mailer123 and mail server address as mail.example.com. Here mail.example.com points to provider mail server which is managing our mail infrastructure. Create a password map file which will contain this information:

There are of course various ways to check whether your mail server is now configured ok or not but what I found is that checking through telnet is quick and easy.

let’s check our mail server now, it may be mail.youdomain.com or localhost depending on what you are using right now, here’s the full process:

# telnet localhost smtp
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 mail.example.com ESMTP Postfix
mail from: me@example.com
250 2.1.0 Ok
rcpt to: other@example.com
250 2.1.5 Ok
data
354 End data with <CR><LF>.<CR><LF>
Subject: Just a test. 
This is test mail using telnet.  
.
250 2.0.0 Ok: queued as 6846838401D6
quit
221 2.0.0 Bye
Connection closed by foreign host.
#_

here,

# telnet localhost smtp

We are trying connecting localhost on port 25 (smtp). It should get connected and ready to accept your next command

mail from: me@example.com

here you are specifying the sender mail id, it should be a valid mail account otherwise mail server can reject the sender address.

I was amazed to hear from my friend that one of their server got hacked and reason may be that their part-time admin set password of root user as ‘admin’. Wow!! can’t believe it! They dont have right to cry about security attacks as they themselves keep their door opens

I’ve suggested them some points as per described below for ensuring secure access to servers. They have 5-6 Linux servers. This is obviously may not be the best way and I’m as always appreciate if you can give your suggestion in comments. My approach is that from 6 servers, we will be able to login only in 2 servers from remote through key based access and from these 2 server, we can access remaining. Here’s what we did:

Hosting my wordpress blog in GoDaddy was a big mistake, I realized this when one of my regular visitor alerted me that my blog is having suspicious activity. I promptly downloaded all of my blog files in my local system to scan and that operation took around 2 hours because of terrible FTP download rate from GoDaddy. Upon looking inside the files, almost all php files were having suspicious code and certainly infected by some malware. I did a clean of each and every file including database scan for any malicious records, users etc (referred this while cleaning). Uploaded all new files by replacing existing completely. I checked my logs and thought for a while about why such thing happened. My wordpress version was latest, strong FTP password and in fact no regular FTP activities from my side. I’ve Mac for myself. So I didnt’ found any reason and forgot that incident.

MySQL stopped default inclusion of InnoDB in latest 5.1.x, so if you need InnoDB, you have to compile it from source. I have done following steps in CentOS 5.4 server to compile MySQL and optimize it later for a heavy site:

1. Remove earlier installation of MySQL, if any and download source rpm from MySQL site. I’ve also removed earlier installation of PHP here to upgrade it:

$ rpm -e php-mysql mysql-server php php-devel php-pear

Download the latest source rpm from MySQL download site, you will get source rpm like below and install it. Installation of source rpm will put it as tar file in /usr/src/redhat/SOURCES, make sure to create /usr/src/redhat/SOURCES directory before installation: