Pages

Friday, April 19, 2013

Conver Putty ppk key to SSH key

In many occasions I needed to convert a Putty ppk private key nack to open ssh key to be able to use it directly from a linux box command line. It is fairly simple to do but I always need to look it up so here it is for easy reference :

Install putty using yum in Fedora.
If you are using Ubuntu you need to install putty-tools as well

From the command line give

puttygen xxxxx2.ppk -O private-openssh -o key.ssh

Enter passphrase to load key:

Then log onto your system using

ssh root@84.200.82.6 -p 8057 -i key.ssh

Tuesday, April 16, 2013

Troubleshooting apache

check httpd service is running or not

• if its not starting the check the syntax of the config file
#httpd -S (display the all files and its location )
#httpd -t or apachectl configtest
if syntax is ok the config file is correct
• check the error logs of apache
/var/log/httpd/error_log
• apache also requires working dsn client support via /etc/resolv.conf and make sure dns is working fine
• check httpd.conf file there is correct entry of server name is there or not and check the port no
• check the size of the log file if it is full then it ll cause error 500 so make sure that log files are under limit and we can us e tool called logrotate in /etc/logrorate.d/httpd create configuration file for httpd log files
• It is possible that some other process may be using port 80 or 443. Use netstat command to list open port and their owners:
#nestat -tulpn
#netstat -tulpn |grep ‘:80′
If other process using port 80 / 443, you need to stop them or assign another port to Apache

What is SPF records and How to setup?

Why Is My Emails Getting As Spam?
Check above things.

First we need to check Email Headers.
1. Return Path
2. To
3. From
4. We should not use CAPS because not only being unprofessional, but it
also triggers spam filters. To land in the Spam folder consistently,
please do not USE ALL CAPS IN THE SUBJECT LINE AND THE BODY FROM TO and
Excessive punctuation (e.g. -/, ;^%#$@+ * "').

E.g. as follows.

1. Email "From : ADMIN ENROLL <noreply@exmaple.com>" getting
spam in gmail.com sometimes and if we not change it will increasing
count.

2. Email "From: noreply@exmaple.com" it
getting in mailbox, check the CAPS deference.

http://php.net/manual/en/function.mail.php
http://www.niso.org/khelp/kmlm/user_help/html/examine_mail_headers.html

Please check this too. It can be understand better. :)
http://www.infusionblog.com/email-marketing/7-ways-for-your-email-to-land-in-the-spam-folder/

Check SPF for Domain.:
http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/

What is SPF records and How to setup?
http://www.kazeli.com/help/index.cfm?pageloc=quest&questid=435&catid=337,338

To diagnose the mail. Why its going in Spam.
Check tool:
http://mxtoolbox.com/
Here you can check following points
1. Mxlookup : For your domain and ip
2. Blacklist : For your IP
3. Diagnostics : SMTP Diagnostics, check your mail server
4. Analyze Headers : Check your mail headers.
5. SPF Records : Check your Sender Policy Framework
7. DNS Lookup : Check your Domain lookup.

If you check above all things your mail will not go in Spam.!

Fast up Httpd

The Apache’s configuration file is located at “/usr/local/apache/conf/httpd.conf” in a cPanel server

Timeout
This directive “Timeout” is used to define the amount of time Apache will wait for a GET, POST, PUT request and ACKs on transmissions before automatically disconnect when idle time exceeds this value. The ideal value will be 120 in heavily loaded servers. It is recommended to set this value lower if your clients have low latencies. Some time, setting this directive to a low value may pause problem, this highly depend on your network and server setup. The best is to experiment with different values to find the one that fit your need.

KeepAlive
This directive “KeepAlive” if set to “On”, enables persistent connections on the web server. For better performance, it’s recommended to set this option to “On” and allow more than one request per connection.

MaxKeepAliveRequests
This directive is used to define the number of requests allowed per connection when the KeepAlive option above is set to “On”. When the value of this option is set to “0″ then unlimited requests are allowed on the server. For server performance, it’s recommended to allow unlimited requests.

KeepAliveTimeout
This directive is used to define how much time, in seconds, Apache will wait for a subsequent request before closing the connection. Once a request has been received, the timeout value specified by the “Timeout” directive applies. The value of “10″ seconds is a good average for server performance. This value should be kept low as the socket will be idle for extended periods otherwise.

MaxClients
This directive is used to define the limit on the number of child processes that will be created to serve requests. The default means that up to 512 HTTP requests can be handled concurrently. This is an important tuning parameter regarding the performance of the Apache web server. For high load operation, a value of “512″ is recommended. For standard use, you can set the value to “256″.

MinSpareServers
This directive is used to define the minimum number of idle child server processes that should be created. An idle process is one which is not handling a request. If there are fewer than “MinSpareServers” idle, then the parent process creates new children at a maximum rate of 1 per second. The idle value is 10
MaxSpareServer
This directive is used to define the maximum number of idle child server processes that should be created. If there are more than “MaxSpareServers” idle child processes, then the parent process will kill off the excess processes and these extra processes will be terminated.The idle value is 15.

MaxRequestsPerChild
This option “MaxRequestsPerChild” is used to define the number of requests that an individual child server process will handle. Set this directive to “0″ to get the maximum performance and scalability for the server.

HostnameLookups
This directive if set to “Off”, specifies to disable DNS lookups. It’s recommended to set this option to “Off” in order to avoid latency to every request, to save the network traffic time, and to improve the performance of your Apache web server.

cpanel exim limit spam

Hello,

The following cPanel/Exim configuration will help you stopping spam in the server.

1. Login to WHM control panel
2. Goto Main >> Service Configuration >> Exim Configuration Manager
3. Enable RBL filtering by Basic Editor >> RBLs >> switch to “On” and if you like you may additional RBL from manage option.
4. Enable Sender Verification by Mail >> Sender Verification >> “On” this will check if the mail origin really exists.
5. Reject SPF failures by ACL Options >> Reject SPF failures >> “On” this will verify SPF records and if the SPF record is set to fails then the E-mails from those IPs will be rejected.
6. Home >> Server Configuration >> Tweak Settings
7. Turn “Initial default/catch-all forwarder destination” to “fail” this will fail the catch all feature to be sent to default cPanel account.
8. “Set Max hourly emails per domain” which will limit the E-mail flooding from the server(I normally set it to 70 which is good enough for a single domain for an hour).
9. Set “Maximum percentage of failed or deferred messages a domain may send per hour” everyone knows that Spam E-mails will have alot of non existing E-mail which will then be deferred so If we set this to say 50% the spamming E-mail account will be suspended temporarily if the deferred mails are above 50%.

10. Then save all the configuration this will stop most of spams in the server.

HOW-TO: Install APC Direct admin

Install autoconf:
Code:
apt-get install autoconf
Install APC using PECL:

Code:

pecl install apc
After install process we have messages like this:

Code:

Build process completed successfully
Installing '/usr/local/lib/php/extensions/no-debug-non-zts-20060613/apc.so'
install ok: channel://pecl.php.net/APC-3.0.19
configuration option "php_ini" is not set to php.ini location
You should add "extension=apc.so" to php.ini
Edit php.ini (via DA or directly: /usr/local/lib/php.ini)
modify extension_dir directive:
Code:

; Directory in which the loadable extensions (modules) reside.
extension_dir = "/usr/local/lib/php/extensions/no-debug-non-zts-20060613/"
Enable extension apc.so:

Code:

extension=apc.so

CustomBuild 2.0 FAQ (DirectAdmin 1.43 or later is needed)

1. What is custombuild?
Custombuild is a tool, which can install/update:
Apache
AWstats
Autoconf
Automake
ClamAV
cURL
Dovecot
Exim configuration files
FreeType
GD
ionCube loaders
libiconv
libjpeg
libpng
libmcrypt
libmhash
mod_perl
mod_ruid2
nginx
MySQL
PHP (mod_php, php-fastcgi, PHP-FPM, suPHP)
ProFTPD
Pure-FTPd
SpamAssassin
Webalizer
Zend Optimizer
Zlib

Update web-applications:
Roundcube webmail
Squirrelmail webmail
phpMyAdmin

How to upgrade custombuild to 2.0?
The best way to do that is a complete reinstallation of CustomBuild, because of changes in configuration files, options.conf etc. Please note that you need DirectAdmin version 1.43 RC1 at least (you can use current pre-release binaries too) to run CustomBuild 2.0.

Code:

+++++++++++

cd /usr/local/directadmin
mv custombuild custombuild_1.x
wget -O custombuild.tar.gz http://files.directadmin.com/services/custombuild/2.0/custombuild.tar.gz
tar xvzf custombuild.tar.gz
cd custombuild
../build
Please check your options.conf file, set the settings you would like to have. The following steps are needed after upgrade of the CustomBuild script, if you would like to use apache:

+++++++++++++++

Code:

../build apache
../build php n
../build rewrite_confs

However, if you want to rebuild everything:

+++++++++++++++++

Code:
../build all d

3. How to install custombuild 2.0?

Code:

cd /usr/local/directadmin
wget -O custombuild.tar.gz http://files.directadmin.com/services/custombuild/2.0/custombuild.tar.gz
tar xvzf custombuild.tar.gz
cd custombuild
../build

You need to run this command for the first time:
Code:
../build all d

=========

http://forum.directadmin.com/showthread.php?t=44743

=========