sandip's blog

Udev is a dependency of xorg and other development packages that breaks OpenVZ containers if installed or upgraded.

Re-create the missing devices after an upgrade via:

For a permanent fix, edit /etc/rc.sysinit to disable udev and auto-repair the devices:

Get status of apache (80) and lighttpd (81) on different ports:

This is done at the nodes.

1. Enable apache server-status in httpd.conf :
   
   <Location /server-status> 
    SetHandler server-status
    Order deny,allow
    Deny from all
    Allow from 127.0.0.1
</Location>
2. Enable lighttpd server-status in lighttpd.conf :
   
   $HTTP["remoteip"] == "127.0.0.1" {
status.status-url          = "/server-status"
}
3. Create /etc/munin/plugin-conf.d/apache:
   
   [apache*]
env ports="80 81" 

   * Test with:
   

   ports="80 83" /etc/munin/plugins/apache_processes

lighttpd idle process will be a straight line as total of busy and idle process is always the same when drawn as STACK, . To change this to LINE1:

At the host, edit "/etc/munin/munin.conf" and add the below line to the corresponding host:

1. Edit conf file: /etc/lighttpd/lighttpd.conf
   
2. Enable mod_expire and mod_compress.
   
3. Expire static files set for 3 days:
   
   $HTTP["url"] =~ "\.(js|css|gif|jpg|png|ico|txt|swf|html|htm)$" { expire.url = ( "" => "access 3 days" ) }
4. Compress mime types:
   
   compress.cache-dir         = "/var/cache/lighttpd/compress/"
compress.filetype          = ("text/plain", "text/html", "text/css", "text/xml", "text/javascript")
5. Cleanup the compressed cache via daily cron script:
   
   #!/bin/bash
# lighttpd_cache_clean
# Clean cache stored at /var/cache/lighttpd/compress
# Place in /etc/cron.daily

# Cache dir path
CROOT="/var/cache/lighttpd/compress"

#Deleting files older than 3 days
HOURS=72

# Lighttpd user and group
LUSER="lighttpd"
LGROUP="lighttpd"

# start cleaning
/usr/sbin/tmpwatch --mtime ${HOURS} ${CROOT}

# if directory missing just recreate it
if [ ! -d $CROOT ]
then
        mkdir -p $CROOT
        chown ${LUSER}:${LGROUP} ${CROOT}
fi

exit 0
6. Create the cache directory and update permissions:
   
   mkdir -p /var/cache/lighttpd/compress
chown lighttpd:lighttpd /var/cache/lighttpd/compress
7. Restart lighttpd.

Below command will convert and create a pdf of a manual page.

Recent upgrade to Apache-2.2.3 secured down on executables not able to be included within a SSI include call and was getting "unable to include potential exec" in the apache error log file.

Apparently .shtml files were being used as includes via SSI. Changing the included files to .html resolved the issue.

Below was the command issued from the document root to quickly rename all the embedded leftmenu.shtml to leftmenu.html:

You can programmatically generate shadow password hash via:

-1 means md5
G5cYam5w is a random salt (minimum 8)
test.123 is the password

Here is the breakdown:

The first $1 means that it is an md5 hash.
The second $G5cYam5w is a random salt.
The third $z0NDUjMRX4xVBKw9Nb6YL0 is the md5 hash.

You can try this to find out if your CPU/Processor is 32 bit or 64 bit:

lm means Long Mode = 64 bit CPU

Also:

Should display 32 or 64.

Recently upgraded server running DirectAdmin to suphp-0.7.1 via the Custombuild. However, got "500 Internal Server Error" on accessing sites running on php5-cgi with log as below:

The solution was to update the suphp.conf file as below:

Edit "/usr/local/suphp/etc/suphp.conf" and change from:

to:

Note the double quotes for the variables.

Running `./build rewrite_confs` should fix this issue as well.

On Debian with Plesk-8.2 installed, /etc/inetd.conf show up with:

Essentially, when the SMTP connection is made, rblsmtpd is handed the connection and does its DNSBL checking. It’s then responsible for either executing the next program (relaylock) if there’s no match, or handles the connection itself if it does find a match. Thus smtp authentication never takes place if your IP is listed in PBL.

On checking Parallels Forum, I came across this post, which suggested:

If you use an dnsrbl in Plesk that lists the IP of someone trying to connect to your server to send email then they will not be able to use your server for smtp on port 25. The dnsrbl will block their attempts. This is normal and expected behaviour in Plesk.

The instructions you read about using authenticated smtp to get around the problem do not apply to the default installation of Plesk (and other similar setups). The idea of the instructions you read is that by using authenticated smtp you will bypass the dnsrbl, and therefore will not be blocked. This does not happen with the default installation of Plesk so the instructions won't work (they are rather simplistic).

The solution in Plesk 8.4 is a simple one. Enable the "submission" option in Plesk, ask your customers to change to port 587 from port 25 in their email clients and require them to use smtp authentication (remember to open up your firewall for port 587 too). This basically creates a second smtp instance listening on port 587 instead of port 25, does not have any dnsrbl blocking and REQUIRES users to use smtp authentication in order to be able to use it. No spam will come via that port because a) server to server email transfer happens on port 25 and b) it requires authentication.

(A similar solution will work in earlier versions of Plesk but rather than ticking a box in the control panel to get it to happen you have to copy a single file and edit two lines in it, but it works just as well and basically does the same thing)

The other option you can go for is to install spamdyke (search the forum for step by step instructions) which does bypass all dnsrbls when smtp authentication takes place. Note that when you use spamdyke you will not be able to use pop-before-relay authentication, and that you set up dnsrbls within spamdyke's configuration files, not via Plesk. spamdyke does add a whole plethora of additional anti-spam measures, however, and it is well worth installing if you don't need pop-before-relay.

Since version of Plesk is older, I put in the below lines in /etc/inetd.conf and restarted inetd.

Now on using the port 587 instead of port 25, users are able to autheticate and send email via the SMTP/Submission server.

1. screen:
   
   screen -dmS <screen_name> <command>
exit
2. nohup:
   
   nohup <command> &
exit
3. at:
   
   echo "<command>" | at now
exit
4. disown:
   
   <command> &
disown -h
exit