Fixing compromised email account on qmail/plesk server

Couple of week before one of Email Server was blacklisted. Reason was one of the email account was compromised and sending spamListed below is the link that nicely explaining how to find that compromised account.

http://major.io/2007/02/10/finding-compromised-mail-accounts-in-plesk/

It was qmail server


transparent squid proxy error

I had setup squid as a transparent proxy. After setting up, still client was not able to access the web page. There was error message logged in by squid server in /var/log/squid3/access.log

The error message was

NONE/400 3505 GET / – NONE/- text/html

Solution :

#vi /etc/squid3/squid.conf

put the word “transparent so the line should look like below

http_port  172.16.26.1:3128 transparent

then /etc/init.d/squid3 restart

Every thing is hunky-dory

Have Fun :)


Recovering or troubleshooting GRUB2 prompt in Debian GNU/Linux

Due to some reason, I was in need to replace existing HDD with new one. So I cloned it using CloneZilla. It was a GNU/Linux Machine. First of all CloneZilla refuses copy partitions, one after another and flagged error for each of one. I remembered the reason for errors and turned off the machine. Turned on again and SHUTDOWN properly. The point is, if Machine is not shutdown properly, file system is unclean and  ColneZilla will complaint while cloning. So I fixed that first. Then cloned without any error. But Computer refuses to boot from newly  cloned HDD. It stayed at grub> prompt

Then I did the following to troubleshoot

Step1. grub> set root=(hd0,1)                                       #  / (root) partition was /dev/sda1

Step2. grub> linux  /vmlinuz root=/dev/sda ro

step 3 grub> initrd /initrd.img

step3. grub>boot

Machines rebooted

on the command prompt as a root

#grub-install  /dev/sda
Rebooted again. Its done.

Reference: https://help.ubuntu.com/community/Grub2/Troubleshooting


Iptables rules to limit time & quota based access

Here are the rules i have add to my GNU/Linux Firewall to limit time and quota for my kids for internet and Xbox live

To limit Quota ( I have just allotted 2GB will increase later on)

iptables -I FORWARD 5  -s 172.16.0.33 -p tcp -m quota –quota 2147483648 -j ACCEPT

iptables -I FORWARD 6  -s 172.16.0.33  -j DROP

For quota ofcourse i have to reset the quota again. I will try to automate it some how

To limit time

iptables -I FORWARD 7 -s 172.16.0.33 -p tcp -m multiport –dport http,https -o eth0 -i eth1     -m time –timestart 16:00 –timestop 18:00 –weekdays Mon,Tue,Wed,Thu,Fri,Sat,Sun -j ACCEPT

Reference:  http://linuxgazette.net/108/odonovan.html

(Above said link had a little typo in time based rule is –days instead of –weekdays


Debian GNU/Linux Nagios3 Bug

I had installed the Nagios3 form package. Installation was fine. I was getting the error message as shown in Screen shot

Even making changes for  ACL’s in Apache conf result noting.

Google is always our friend.The link shown below explained about the bug.

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=626462

I have changed file as shown

Added the index.html in /etc/apache2/conf.d/nagios3.conf. So the line should be

DirectoryIndex index.php  index.html

not

DirectoryIndex index.php

/etc/init.d/apache2 restart

Done!

Have Fun


Ucarp setup for Debian Squeeze

It was easy

Do the following on both  Load Balancers ( I did it on Nginx LBs)

1. apt-get install ucarp

2. vi  /etc/network/interfaces and append the lines starting from ucarp-vid 3

3. replace password and ip (192.168.69.11) with your own

4. Reboot

I have followed the link below. Tested it by shutting down both Load Balancers one by one.

Will dig more in to it. It is Awesome!.

Reference http://forsetti.wordpress.com/2011/09/10/ucarp-and-squeeze/

Have Fun :)

 


GNU/Linux Screen Utility

screen command refrence nice link

http://aperiodic.net/screen/quick_reference

 

Have FUN :)

 


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