fduran

# www.fduran.com
# Check which Linux users could log in with password, see "man shadow" for the second field in the /etc/shadow file:
# "If the password field contains some string that is not a valid result of crypt(3), for instance ! or *, the user will not be able to use a unix password to log in (but the user may log in the system by other means).
# this awk one-liner will find users that have common used * or ! in the password field or field starts with ! (locked account). It's possible that still found user cannot log in due to other non-crypt character in the field

awk -F: '$2 != "*" && $2 !~ /^!/ { print $1, " can log in" }' /etc/shadow

fduran

# www.fduran.com
# installing mod_security http://www.modsecurity.org (Debian-based distro)

# apachectl -M
apache2: Could not reliably determine the server's fully qualified domain name, using boxmetric.com for ServerName
Loaded Modules:
 core_module (static)
 log_config_module (static)
 logio_module (static)
 mpm_prefork_module (static)

fduran

# www.fduran.com
# hardware stress test
# mismatched md5sums shows a faulty disk/RAM  
# time depends on hardware, ex: 1 sec per 100 count
dd if=/dev/zero of=/tmp/test.file bs=1M count=1000
for i in {1..5}; do md5sum /tmp/test.file; done

fduran

# www.fduran.com
# Linux honeypots

# nephentes
# (google 'nephentes honepot')
apt-get update; apt-get install nepenthes
nano /etc/nepenthes/nepenthes.conf
/etc/init.d/nepenthes restart
#log: less /var/log/nepenthes.log

fduran

www.fduran.com
Remote syslogging in Linux

1. On logging server 'logserver':
# nano /etc/rsyslog.conf

uncomment:
# provides UDP syslog reception
$ModLoad imudp
$UDPServerRun 514

fduran

www.fduran.com
Monitoring Plesk with Monit

Plesk is not mentioned anywhere in monit's site http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=plesk+site%3Ammonit.com and I couldn't find any article or tutorial about how to monitor Plesk using Monit, so I'm writing one myself in the hopes other people with the same problem find it.
	
Plesk 8.3 on Centos5	
	
etc/init.d/psa status
psa dead but subsys locked

fduran

# www.fduran.com
# Linux check DNS cache snooping
# check if somedomain (try popular ones like google.com etc) is cached in a dns_server

# with nslookup
nslookup -norecurse somedomain dns_server

# with dig
dig @dns_server somedomain A +norecurse

fduran

# www.fduran.com
# Linux shell "here" document

$ cat > newfile << EOF
> write something
> EOF

# obv also:
$ cat > newfile
# and Ctr-D

fduran

# www.fduran.com
# Heroku notes for python, fixes http://devcenter.heroku.com/articles/python
# Ubuntu 11.04 (Natty Narwhal)

mkdir heroku
cd heroku

# Prerequisites
curl -O https://raw.github.com/pypa/virtualenv/master/virtualenv.py
cp virtualenv.py /usr/bin/virtualenv

fduran

# www.fduran.com
# apache password protect directory

# Apache config
<Directory /home/user/public_html>
	AllowOverride AuthConfig
	# ...
</Directory>
        	
Alias /protected "/home/user/public_html/protected"