Admins eHow SysAdmin Tips & Tricks

July 29, 2010

GET: command not found

Filed under: Debian — Tags: , , , — admin @ 4:41 pm

if you get the following error on debian :

-bash: GET: command not found

install the following package :

apt-get install libwww-perl

April 30, 2010

Connect to PPTP VPN from Linux only by one command

Filed under: CentOS,Debian,General — Tags: , , , , , , , , , — admin @ 1:03 pm

I’ve used this method to connect to a windows PPTP VPN server on PCLinuxOS 2010 , but I am sure it will work on other ditros too.
First make sure sure pptp-linux and ppp packages are installed on your client PC.
you may install them by yum or apt-get or package manager of your linux.
then use the following command to connect to VPN.

pppd pty "pptp IP_OR_FQDN_VPN_SERVER --nolaunchpppd" file /etc/ppp/options.pptp user USERNAME password PASSWORD

replace IP_OR_FQDN_VPN_SERVER with IP or DNS of your VPS server.
replace USERNAME with your VPN username.
replace PASSWORD with your VPN password.
wait for like 10-15 seconds , then run ifconfig command , you should see ppp0 interface there , if it is not there , you can troubleshoot by looking into syslog of your linux.
please note this command is good for connecting to a windows VPN server with default configuration , if you have any custom settings , you may need to edit /etc/ppp/options.pptp file.
to disconnect form VPN , use the following command :

killall pppd

if you need to route all of your traffic to VPN server ( use it as a gateway ) , do the following :
create a file named vpn-up in /etc/ppp/ip-up.d and put the following lines inside it :

H=`ps aux | grep 'pppd pty' | grep -v grep | awk '{print $14}'`
DG=`route -n | grep UG | awk '{print $2}'`
DEV=`route -n | grep UG | awk '{print $8}'`
route add -host $H gw $DG dev $DEV
route del default $DEV
route add default dev ppp0

and make it executable by :

chmod +x vpn-up

create another file named vpn-down in /etc/ppp/ip-down.d and put the following lines inside it :

H=`route -n | grep UGH | awk '{print $1}'`
DG=`route -n | grep UGH | awk '{print $2}'`
DEV=`route -n | grep UGH | awk '{print $8}'`
route del -host $H
route add default gw $DG dev $DEV

and make it executable by :

chmod +x vpn-down

now reconnect to VPN , and your routing will be done automatically.

March 31, 2010

Check e-mail on a pop3 server using telnet

Filed under: General — Tags: , , , , , , , , , — admin @ 9:44 am

These steps show how to check your e-mail on a pop3 server using a telnet client.

Telnet to the pop3 server.

telnet 110

You should recieve a reply to this effect.

Trying A.B.C.D...
Connected to
Escape character is '^]'.
+OK (rwcrpxc13) POP3 server

if you want to connect to a pop3 SSL server use the following command on a linux shell :

openssl s_client -connect FQDN:PORT

for instance for gmail it is :

openssl s_client -connect

You will get a response like this :

depth=1 /C=US/O=Google Inc/CN=Google Internet Authority
verify error:num=20:unable to get local issuer certificate
verify return:0
Certificate chain
 0 s:/C=US/ST=California/L=Mountain View/O=Google Inc/
   i:/C=US/O=Google Inc/CN=Google Internet Authority
 1 s:/C=US/O=Google Inc/CN=Google Internet Authority
   i:/C=US/O=Equifax/OU=Equifax Secure Certificate Authority
Server certificate
subject=/C=US/ST=California/L=Mountain View/O=Google Inc/
issuer=/C=US/O=Google Inc/CN=Google Internet Authority
No client certificate CA names sent
SSL handshake has read 1703 bytes and written 300 bytes
New, TLSv1/SSLv3, Cipher is RC4-MD5
Server public key is 1024 bit
Compression: NONE
Expansion: NONE
    Protocol  : TLSv1
    Cipher    : RC4-MD5
    Session-ID: AF09D6024039D1F70D7A6518034EF3B2E1B949C15A71ED3D0E85BC89F7D4ADC2
    Master-Key: 58D4202B16256CA5715C45B2CDDDFDDC16ABCAEF2A0993D23F3817193AE3F4A4E5531EF13CA970BADD1F8EA273FD6871
    Key-Arg   : None
    Start Time: 1270025037
    Timeout   : 300 (sec)
    Verify return code: 20 (unable to get local issuer certificate)
+OK Gpop ready for requests from a.b.c.d q9pf826547gve.29

Enter your username for the pop3 e-mail account using the “user” command.

user username_here

You should recieve the following reply.


Enter your password for the pop3 e-mail account using the “pass” command.

pass password_here

You should recieve the following reply.

+OK Maildrop ready

Stat your mailbox using “stat” command.


You will get response showing the number of messages on the server and total size of them.

+OK 2 9141

List the mail on the pop3 e-mail account using the “list” command.


You will see the list of messages on the server.

+OK scan listing follows
1 1489
2 7652

To see one of the messages issue the retrieve command “retr” and the message id.

retr 1

You will see the whole e-mail headers and all.

+OK 1489 octets
Received: from blah ( [a.b.c.d])
(iPlanet Messaging Server 5.2 HotFix 1.16 (built May 14 2003))
with ESMTP id <> for; Wed, 02 Jul 2003 23:54:23 -0400 (EDT)
Date: Wed, 02 Jul 2003 23:52:59 -0400
From: Me
Subject: test
Message-id: <>
MIME-version: 1.0
Content-type: text/plain; charset=us-ascii
Content-transfer-encoding: 7bit
Content-disposition: inline
User-Agent: KMail/1.5.1
Original-recipient: rfc822;


If you would like to delete the message issue the dele command with the message id.

dele 1

You will then see a delete confirmation.

+OK message deleted

To finish issue the quit command.


Response :

Connection closed by foreign host.

September 10, 2009

Show Apache loaded modules from shell

Filed under: Apache,CentOS,Debian,General — Tags: , , , , — admin @ 4:25 pm

This command shows both static and shared loaded modules in Apache :

httpd -M

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