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how to test the plain and encrypted SMTP/POP3/IMAP and HTTP protocols

In this article I will describe how to test the plain and the encrypted SMTP/POP3/IMAP and HTTP protocols with telnet and the openssl s_client command.

list of references

For a complete list of available commands for the used protocols check the RFCs please:

SMTP sending mail

In the first example I will open a telnet connection to a SMTP Server on …

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pipe viewer – monitoring / limit the throughput of a pipe

Pipe viewer is a command line tool which is used to monitor the throughput, display the estimated time of completion or to limit the transfer rate of a pipe (pipeline).

Install pipe viewer on Debian / Ubuntu with the following command.

apt-get install pv

On CentOS / Fedora / RedHat use the yum command to install pipe viewer

yum install pv

To use pipe viewer just insert the pv command between two processes to monitor the throughput of the pipe.

cat logfile.log.1 | pv | gzip -9 > logfile.log.1.gz
9,18MB 0:00:01 [ 9,1MB/s] [   <=>

Or limit the transfer rate of the pipe to a designated number of bytes.

cat logfile.log.1 | pv --rate-limit 100 | gzip -9 > logfile.log.1.gz
 300B 0:00:03 [ 101B/s ] [         <=>                                    ]

Related Posts:

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Dumping HTTP header with ngrep – the network grep

To get the HTTP Header informations for specific clients connections use ngrep and a pattern or a regular expression that will match the packets.

install ngrep (example for debian / ubuntu):

apt-get install ngrep

These examples dumps HTTP header for any connection matching the string “images” on port 80.

user@host:~# ngrep -qi -W normal '/images/'  port 80
interface: lo (
match: /images/

T -&amp;gt; [AP]
GET /images/globe_blogs.gif HTTP/1.1..Host: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; de; rv: Gecko/20101026 Firefox/3
.6.12..Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8..Accept-Language: de-de,de;q=0.8,en-us;q=0.5,en;q=0.3..Accept-Encoding: gzip,deflate..Ac
cept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7..Keep-Alive: 115..Connection: keep-alive..Cookie: …
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Liveblogging at Confoo: [not just] PHP Performance by Rasmus Lerdorf

Most of this stuff is not PHP specific, and Python or Ruby or Java or .NET developers can use the tools in this talk.

The session on, with user comments/feedback, is at

Slides are at

“My name is Rasmus, I’ve been around for a long time. I’ve been doing this web stuff since 1992/1993.”

“Generally performance is not a PHP problem.” Webservers not config’d, no expire headers on images, no favicon.

Tools: Firefox/Firebug extension called YSlow (developed by yahoo) gives you a grade on your site.

Google has developed the …

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Debugging AMP

In a previous post, I mentioned the availability of the dtrace extension for Cool Stack's PHP.  Using this extension and the Cool Stack MySQL, it is possible to analyze the performance of your application running on this stack. At JavaOne, we demoed this using the open source MediaWiki and SugarCRM applications.  dtrace is especially useful in analyzing complex multi-tier applications like AMP. Thanks to Angelo Rajadurai for the creation of the scripts that I describe below.

Analyzing PHP calls

So, let's look at a simple dtrace script that counts how many times a particular PHP function is called :

#!/usr/sbin/dtrace -Zqs


You can copy the …

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