Posted inperl smtp

Measure Response Time Of SMTP Connections Using Perl

Normally, to check if my server smtp connection alive, I just do telnet to port 25 from my workstation. if the smtp banner displayed, it means that the connection to the smtp server is good. I have done this for years.  😆

$ telnet smtp.example.com 25
Trying xxx.xxx.xx.xxx...
Connected to xxx.xxx.xx.x.
Escape character is '^]'.
220 smtp.example.com ESMTP Postfix
ehlo host.example.com
250-smtp.example.com
250-PIPELINING
250-SIZE 52428800
250-ETRN
250-STARTTLS
250-AUTH LOGIN PLAIN
250-AUTH=LOGIN PLAIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
quit
221 2.0.0 Bye
Connection closed by foreign host.

Although many tools that are deliberately created for this purpose, still, I prefer just using telnet to port 25. I have made a simple perl script, with the intention that the things I do for years manually can be done automatically.

Modules required:
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Posted innginx

Nginx, Simple Http Authentication Using ngx_http_auth_pam_module Module

I already have a list of users in a mysql database that I use for postfix smtp authentication/sasl.

I wonder, whether the list can be used for http authentication 😀 . Well, let’s find out.

First of all, of course we must compile nginx to support http_auth_pam_module module.
download ngx_http_auth_pam_module-1.2.tar.gz

When compiling from source build as usual adding the -add-module option:

./configure --add-module=$PATH_TO_MODULE

My pam_mysql for postfix smtp authentication /etc/pam.d/smtp

auth required pam_mysql.so user=user passwd=pass host=localhost db=db table=mailbox usercolumn=username passwdcolumn=password crypt=1 md5=1 sqlLog=0
account sufficient pam_mysql.so user=user passwd=pass host=localhost db=db table=mailbox usercolumn=username passwdcolumn=password crypt=1 md5=1 sqllog=0
Tags: , 1
Posted innginx

Nginx, Strip All Newlines Using nginx-nonewlines Module

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Nginx

Another Nginx module i’ve tested today, nginx-nonewlines , basically, this module same as Evan Miller’s nginx mod_strip module , Evan Miller’s mod_strip module removes unnecessary whitespace (spaces, tabs, and newlines) from HTML documents and automatically leaves comments as well as <pre></pre> tags untouched. while using using nginx-nonewlines we should define  <!–SC_OFF–> and  <!–SC_ON–> within the html code area that we’re intend to leaves them intact.

Here’s quick and dirty compiling nginx-nonewlines module

  • download the module
https://github.com/vedang/nginx-nonewlines/archives/master
  • add this line to ./configure step, compile and install
  # ./configure \
  ....
  ....
  --add-module=/path/to/vedang-nginx-nonewlines-ba02b59
  ....
  ....
  # make && make install

add folowwing directive to nginx’s config.

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Posted inpostfix

postfix-2.9.20110605 rpm source

postfix-2.9.20110605.src.rpm Changelog 20110516 Update the warning when permit_naked_ip_address is used, and add permit_sasl_authenticated to the list of suggested alternatives. File: smtpd/smtpd_check.c. 20110601 Bugfix (introduced Postfix 2.6 with master_service_disable) loop control error when parsing a malformed master.cf file. Found by Coverity. File: master/master_ent.c. 20110602 Bugfix (introduced: Postfix 2.7): "sendmail -t" reported…
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Posted innginx

Nginx Blocking Spoofed Google Bot

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Nginx

I’ve found something interesting in the nginx mailing list today http://forum.nginx.org/read.php?2,202715,202715#msg-202715 . someone asked whether it is possible to block fake user agent such as google bot. sometimes, a lot of bots flood our servers disguise as google bot or other legal bot. Most likely, to scrape our website’s contents. Original google bot always uses the ip address which is owned by Google Inc. Many website owners complained, bad bots only drain their bandwidth usage. 🙂

The first option to use “if” directive in nginx.

if ($http_user_agent ~* "Google Bot") {
	allow 66.x;
	allow 70.x;
	deny all;
}

However, “if” directive considered to be a bad practice when use for anything rather than “return” or “rewrite”. Here’s an example from Igor Sysoev:

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