Server response: No properly formed ip addresses

The other day I was looking into a problem on one of our hosting servers running Parallels Plesk 8.6. The server's license had just entered his grace period and retrieving the key resulted an error message as "Server response: No properly formed ip addresses" which seemed very odd! At first I thought maybe its a firewall issue but I was wrong. For me restarting the httpsd service resolved the issue (/usr/local/psa/admin/bin/httpsdctl restart) but I couldn't find out the root cause.

Cisco beginner command cheat sheet

I was thinking of a Cisco beginners / Essential command cheat sheet so I started looking around and came across the following which was helpful but not what I was exactly looking for and thought it might be good idea to share it. It includes more than 20 cheat sheets:
Cheat Sheets - PacketLife.net

Cryptography FAQ

If you are looking for a reference to understand Cryptography the following is a good starting point:
Crypto FAQ
It does not provide details on all the concepts and as the title says, it is just an FAQ and gives you an overall view of all the cryptography jargon!

A PDF version is available at:
ftp://ftp.rsasecurity.com/pub/labsfaq/rsalabs_faq41.pdf
or
http://www.rsasecurity.com/rsalabs/faq/files/rsalabs_faq41.pdf

Openfire an easy to use IM Server

Openfire (formerly wildfire) from "Ignite Realtime" is a free and easy to install IM server based on XMPP protocol which is available for Windows, Linux and Mac platforms.
I have tried the windows version and it worked nice. Its client is named "spark" and there is a web-based client (Sparkweb) available as well.
I got to this simple and easy IM server while I was searching for a Linux client for Microsoft Live Communication Server. I have crawled a lot a of forums and after all it seems that there is no solution to that in the Linux world yet. Some posts on using Wine was available but the people who tested it didn't come out with a positive result.

My Firefox Add-ons

Here is the list of my favorite firefox add-ons:
FireFTP:
Des: Easy to Use FTP Client
Link: http://fireftp.mozdev.org/
Domain Details:
Des: Displays Server Type, IP Address with Location Flag.
Link: https://addons.mozilla.org/en-US/firefox/addon/2166
Live IP Address:
Des: Displays your IP address in Status Bar
Link: https://addons.mozilla.org/en-US/firefox/addon/1731
ScreenGrab:
Des: Saves current web page or part of it as image file
Link: Screengrab! :: Firefox Add-ons
Read it later:
Des: The title explains what it does!
Link: https://addons.mozilla.org/en-US/firefox/addon/7661
Showcase:
Des: A thumbnail view of currently opened tabs
Link: Firefox Showcase :: Firefox Add-ons
Download Statusbar:
Des: The title explains what it does!
Link: Download Statusbar :: Firefox Add-ons
ReloadEvery:
Des: Reloads your pages automatically on every x seconds
Link: ReloadEvery :: Firefox Add-ons
HTTP Live Header:
Des: Shows the http dialogue between your browser and the destination web server.
Link: https://addons.mozilla.org/en-US/firefox/addon/3829

Make Putty Tab Based!

Everyone knows Putty well but I always prefer to use SecureCRT because I can open different connections in a tab based manner, I can easily clone my sessions in case I need more than one session to the same device mainly for debugging or diagnostic reasons and I can save my connections into a database which easily can be backed up (Putty stores the sessions into registery!).
The good part about Putty is free, it is handy and requires no installation!
Well there are always great people out there to make things work better and thanks to Ramesh I have leaned that there is a free add-on called "Putty Connection Manager" which does all the job I pointed out earlier. You have your Tabbed based interface, You can clone your sessions and everything is stored in a database and above all it makes putty look more modern ;)
There are many other useful add-ons for Putty and you can learn about them through the following link:
The Geek Stuff » Turbocharge PuTTY with 12 Powerful Add-Ons - Software for Geeks #3:

Email Security Vocabulary!

Improve your email security Terminology:

• Domainkeys (http://en.wikipedia.org/wiki/DomainKeys)
• DKIM (http://en.wikipedia.org/wiki/DomainKeys_Identified_Mail)
• SenderID (http://en.wikipedia.org/wiki/Sender_ID)
• SPF (http://en.wikipedia.org/wiki/Sender_Policy_Framework)
• BATV (http://en.wikipedia.org/wiki/Bounce_Address_Tag_Validation)
• DNSBL (http://en.wikipedia.org/wiki/DNSBL)
• Spamtrap (http://en.wikipedia.org/wiki/Spamtrap)
• DCC (http://en.wikipedia.org/wiki/Distributed_Checksum_Clearinghouse)
• Greylisting (http://en.wikipedia.org/wiki/Greylisting)
• Nolisting (http://en.wikipedia.org/wiki/Nolisting)
• Callback Verification (http://en.wikipedia.org/wiki/Callback_verification)
• Spamassassin (http://en.wikipedia.org/wiki/SpamAssassin)
• Bayesian Filtering (http://en.wikipedia.org/wiki/Bayesian_filter)
  
• Backscatter (http://en.wikipedia.org/wiki/Backscatter_(e-mail))
• Hashcash (http://en.wikipedia.org/wiki/Hashcash)
• Tarpitting (http://en.wikipedia.org/wiki/Tarpitting)

Dig DNS Lookup in Windows!

Every System Administrator dealing with DNS administration knows the power of "dig" command-line tool in Linux/Unix environment. But there are times when an administrator needs to monitor and troubleshoot DNS from a Windows station and she would then realizes the deprivation!
The good news is that many Linux/Unix tools have been ported to windows (Check my post about Windows IPFW) and one of them is the "dig" utility.

The windows version of "dig" can be downloaded and installed from here: http://members.shaw.ca/nicholas.fong/dig/


For those who are new to "dig" the following link helps:
Dig Howto: http://www.madboa.com/geek/dig/

A great Free IE7 add-on

IE7Pro is a free IE7 add-on which brings a lot of great features to your browsing.
The followings are the features I like the most about IE7Pro:
Search Bar: This makes IE7 search like Firefox which brings up a search bar and you can run live lookups.
Tab History: Keeps a history of all opened tabs and I can easily browse from this list
Tab Recovery: If for any reason IE7 closes unexpectedly and I have had a couple of opened tabs it will show me the list of opened tabs the next time I run IE7.
Save Session: if I save a session by loading it the next time it will open all tabs I had open at time the I saved the session. (Very useful and time saving)
Save Pages as Images: This is really wonderful! I can save a whole page in .PNG format and it works very quick.
Page Auto Refresh: This way I can set an interval on each tab which IE7 will automatically reload the page!
Auto-scroll: Once enabled it will scroll down a page automatically with a tunable speed.

Fighting Spam with Barracuda Spam Firewall

It's been a couple of weeks since I started working on a dedicated solution to fight incoming spam and I did some study on the history and mechanisms available to block spam and which methods are efficient for an Internet Data Center. I was thinking of implementing Spamassassin using Qmail as MTA, but our company policy has changed and now I am considering an Anti-spam Appliance. There are many appliances available and most of them have other security features like Firewalling, Virus scanning and DoS protection.
Spam Firewall from Barracuda Networks seems a great option to me with different mechanisms including Bayesian and great control over what should be considered spam and non-spam (ham) and provides a good visibility to what is happening on the box by its statistics. Its control panel has got a lot of screens which might bring complexity but it also gives great control and make any policy enforcement possible!
I am really impressed with the administration options and I like to get my hands on it!
Spam Firewall is actually a Linux platform running spamassassin in its core.

Free Windows TFTP and Syslog server!

It might sound crazy but I got a Cisco PIX firewall at home (PIX 501) and my internet traffic is running through it with a PPPoE connection and I have configured it to accept remote VPN connections as well in case I need to access my data at home while at work.
I was looking for a free and light TFTP server to backup my PIX configuration regularly and I found exactly what I was looking for at http://tftpd32.jounin.net/. tftpd32 is not just a TFTP server but also a DHCP and Syslog server as well. The next question was running TFTP as a service which I found the answer here: HOW TO install Windows tftpd as service.

How to Implement Source Routing With Linux

As mentioned in my previous post I got an Internet gateway which is a Linux box and I have two Internet connections connected to that server. One is a 2Mbps Leased-Line and the other a 1Mbps wireless connection. I want hosts from specific subnets have their Internet traffic directed to the wireless Internet connection while others go through the Leased-Line link.

This is easily done with Linux and iproute2 suit which is installed by default on Fedora.

By default all routes are stored in a table called "main" and by issuing the following command the routes stored inside this table can be displayed:

• ip route list table main
  

The results are exactly that same as just running the "route" command.

Any queries coming to this server for routing decisions will be looked up in the "main" table unless mentioned otherwise. But how is this possible?

It is also possible to define a new routing tables and have different routing entries inside the new defined table and apply rules so that traffic from specific sources are directed to this new table for route look up!

First:

we need to create a new table which easily handled by adding the name at the end of /etc/iproute2/rt_table. It may look like this:

10 wireless-link

Second:

New routes should be added to this table:

• ip route add 192.168.120.0/24 via 192.168.10.1 table wireless-link
• ip route add default via 80.120.99.12 table wireless-link (This defines the default route for "wireless-link" routing table)
• ip route list table wireless-link (This will display routes added to wireless-link)

Third:

Route rules must define when requests must be looked up in the "wireless-link" table!

• ip rule add from 192.168.120.0/24 table wireless
• ip rule list (display ip rules)

From now on, every traffic coming from 192.168.120.0/24 will be leaded to wireless-link table so its default route will be 80.120.99.12 while traffic from other sources will be still lookup routes in the "main" table which has its own default route (Leased-Line).

To undo ip rules and routes the following syntax must be followed:

• ip rule del from 192.168.120.0/24 table wireless
• ip route del default via 80.120.99.12 table wireless-link

Linux Traffic Control, DNS ALG issue , and Service Monitoring

I am busy with a couple of interesting stuff that keeps me away from posting here.
First,
I am working on a linux box which is an internet gateway and controls traffic using iptable and at same time it acts as the inter VLAN router for around 10 VLANs using 802.1Q. I am trying to run some sort of QoS to put traffic control on every VLAN for their internet usage. And with Linux this will be easily done with a tool called TC.
I have expressed that before but it is worth to mention again that with linux we will get tons of outstanding networking features that gives us full control on our network and what is running behind the scene on the wires! I am really impressed!!!
Second,
My firewall is not handling DNS ALG as expected so it has brought us some disturbance. Everything is fine with outside to inside regular DNS queries but when a DNS query for PTR record comes in, DNS ALG does not translate the IP address in the response payload while it does so when it comes to Forward queries. According to RFC 2694 this should work unless our Firewall is not RFC compliant. I am documenting the issue regarding RFC to send it over to our Firewall Vendor.
Third,
I was studying available service monitoring tools to monitor our IDC services and servers and nearly reached to the conclusion to implement "ManageEngine Applications Monitror" and I already have a pilot server in place. I will post on it later.

Monitoring in a Data Center

I was thinking what we need to consider for a thorough monitoring strategy in an IT environment like a Data Center. There are various areas that should be monitored to meet High Availability. Monitoring can be categorized as follow:

• Physical Access
• Environmental Parameters
• Hardwares
• Bandwidth Usage
• Server Connectivity
• Server Resources Usage
• Service Availability
• Traffic Analyzing
• Log Analyzing

For each monitoring category there are many tools available both commercial and free (Mainly Open Source) that can be obtained and implemented. Some tools might cover more than one of the above categories and some just limited to a single category.
Having all of these monitoring services and procedures in place might be too expensive for some organizations and based on priorities and needs one or some of the above might be picked up.
I will post more about monitoring later.

Did you know when to use Bcc?

I had a topic on the Persian section of my website titled "when to use Cc or Bcc in our Emails" about three years ago. Those who didn't learn when to use Cc or Bcc can see the consequences here:


Thanks Babak for pointing this out to his blog visitors!

"IE view" and "PDF Download" Firefox Extensions

Feel more comfortable with these two Firefox extensions:
IE View:

Adds "View page in Internet Explorer" links to the content and link context menu. Handy for previewing pages in IE, loading up IE-only pages when you run across them in Mozilla, etc.

PDF Download:

Allows to choose whether you want to view a PDF file inside the browser (as PDF or HTML) or you want to download it

Backup Sharpreader Subscriptions

Backing up Sharpreader subscriptions and settings is easily done by copying the content of the following location:

drive:\Documents and Settings\username\Application Data\SharpReader

The subscriptions are all in a file named "subscriptions.xml"

POP3 enabled by GMail

To me,This is unbelievable! GMail is giving its users the great opportunity to use a mail client to send and receive emails through POP3/SMTP! Good news for everyone and may be shocking to GMail competitors and opponents as its 1GB service was!
Like me, you may not see the settings described in the following location but don't worry these wonderfull guys are adding this feature to every GMail user but in phases.
Gmail: Help Center
Gmail: Configuring GMail for Outlook 2003

How to Add Google Search Box

You may have noticed a new search box from google on the right column of this blog! Adding a google search bar to your blog is free and very easy just follow the link and customize your own search box:
Want to drive traffic? Try the Google Free way.

Firefox RSS Live Bookmarks

This is a fascinating and innovative feature that Mozilla has added to its firefox version 1.0 preview release. Cool for everyone especially for those without a feed reader. With Live Bookmatrks feature available on this version an RSS symbol appears on the bottom right corner of the browser on RSS enabled websites. Once a site is added to the bookmark list the latest posts are dynamically added to the contents of that bookmark entry so that it keeps you update.
Mozilla Firefox - Live Bookmarks

Clear Cookies to Fix Gmail Notifier Bad Data Issue

I could finally find the resolution to Gamil Notifier "Can not read your messages (bad data;1)" problem. Just close the notifier from system tray and clear your cookies. If it didn't work uninstall Gmail Notifier, clear cookie and then install notifier again.
Clearing Cookies in Mozilla Firefox:
Tools>Options>Privacy>Cookies>"Clear"
Clearing Cookies in IE:
Tools>Internet Options>"Delete Cookies"

Update:
Thanks for everyone for their helpful comments on this post. I have included some of them as part of the main post:

Anonymous:
You don't need to delete all your cookies! Just delete those of them that are like this ...@gmail... and ...@google...
And stop the notifier before that.

fridgemagnet:
Note - even if Firefox is your main browser, if you've ever looked at google on IE, you will also need to clear cookies on IE as well. Clearing on both should fix it (did for me anyway).

Google Desktop Search Available!

I have just learned (through Ali's weblog) that google has released its beta version of desktop search engine. This desktop engine can index Microsoft Outlook/Outlook Express, Word, Excel, PowerPoint files as well as local web history, text files and even AOL IM based on users preferences configuration. The search results are presented in web browser and can be sorted by date or relevance. It is also possible to filter results to show only files, emails, chats, and web history. The search engine starts indexing when the system is idle so it doesn't impress system performance during activity.
I have been using Microsoft "Lookout" since its release and experienced performance issues but didn't notice any such issues on Google Desktop Search Engine yet.
Download a free copy from here:
Google Desktop Search Download

Love It But Can Not Trust It!

Notices the following issues on my Firefox since now:
- High CPU utilization on PDF pages
- System crashes when lots of tabs are open and in the loading state at the same time
- In some occasions the cache mechanism stopped loading websites (Gmail) and clearing the cache was the work-around solution
- It does not support FlashGet
- Some websites can not be shown as supposed
This doesn't mean I am giving up on firefox but it means I am expecting compatibility and stability improvements by providing updates and hotfixes soon.

Gmail Notifier: Can not read your messages

It has been a week since my Gmail Notifier stopped functioning correctly saying "Can not read your messages (bad data;1)" So I need to check my Gmail box manually :(

Outlook 2003 Junk E-mail Filter Update

Microsoft has released another update to Outlook 2003 Junk Email Filter which enhances junk e-mail detection:
Download details: Update for Outlook 2003: Junk E-mail Filter (KB870765)

New Feature: Email Posts to Friends

Blogger has added a new feature to its blogging service letting people email posts to their friends.

Further information on this new feature Here

HTTP Header Monitoring Add-ins for IE and Firefox

IEHttpHeaders is a free add-in that shows Sent and Received HTTP Headers traffic in IE within an Explorer bar. There is also an alternative for Firefox and Mozilla users called "Live HTTP Headers" that shows the same stuff!

Get Informed by Gmail Notifier

Finally we have it! Now Gmail users can be notified about new mails arrived at their Gmail mailbox by Gmail Notifier sitting in system tray.

Download it from Here:
Gmail Notifier
To learn how Gmail can be configured as the default mail application and how audibe new mail notifications can be set check the FAQ section.

Top tips for Outlook 2003

This topic is a digest of all features every Outlook 2003 user needs to know and great tips to make living easier with outlook 2003. Covers email, calendar, contact, keyboard shortcuts, customization, notes and task tips. Worth reading it even for Outlook gurus!
Microsoft Office Assistance: Top tips for Outlook

Gmail stopped working on Firefox!

For two days I had the same problem and thought it was a Gmail issue but after clearing out Firefox cache now I have my Gmail back in firefox.
David Ely: Gmail and Firefox for Windows Problem

Missing BlogThis on Firefox?

As a blogger I was missing the "Blog this!" button on Firefox since I moved from IE but there is always an alternative in Firefox for features available in IE and most of these alternatives come with Firefox Extensions. by having this extention installed the "Blog This!" comes back on the browser but on the context menu:
Extension Room :: BlogThis

Lookout Your Desktop Search Engine!?

This Outlook Add-in is now free for everyone! And can be downloaded from Microsoft Download Center. Once installed it will index all the data on Outlook (Emails, Tasks, Calendars, Contacts, Notes and Posts) and additional folders outside outlook on any drive can also be set to be indexed which turns this add-in into a desktop search engine without exaggeration.
It also gives the option to restrict search to specific times, only contacts, only emials, only in files or results with attachment.
Download details: Lookout V1.2

UPDATE: I don't know why but Microsoft has removed Lookout from its Download Center! Lookout can be downloaded from "Lookout Software" website.

Gmail and Firefox

Mozilla Firefox Extentions are actually plug-ins that add new functionalities to the browser and at the time of writing this post there are 196 extensions available for Firefox. The Extension Room can be reached at:
Extension Room

Many Extensions are available and I have to spend some more time on the list. Among those I have checked yet I found the GmailCompse extension interesting. This Firefox Extension Adds a context menu link for opening a GMail compose window when clicking on mailto: links and text email addresses:
GMailCompose

How To Backup FireFox Bookmarks(Favorites)

I make regular backups of my Internet Explorer favorites which are placed in a folder named "Favorites" inside the user profile. In IE for every entry added to the favorites an Internet Shortcut (*.url) is created so the backup is actually a container of files with the url extension. Now that I am switching to FireFox it is important to keep my backup schedule but FireFox is using a different mechanism to store bookmarks! Instead of creating an entry for every bookmark it uses a single HTML file to hold the entire bookmarks and this HTML file is located in the user profile:

"Drive:\Documents and Settings\username\Application Data\Mozilla\Firefox\Profiles\default.qfb\bookmarks.html"

So by backing up "bookmarks.html" I will have my backup in place again and FireFox gives me the ability to search through my Bookmarks by keeping all the entries in this HTML format.



UPDATE: This Firefox extension makes daily bookmark backups automatically and puts them in the Firefox profile directory:

C:\Documents and Settings\username\Application Data\Mozilla\Firefox\Profiles\default.qfb\Backups

Extension Room :: Bookmark Backup

Switching to Firefox Browser?

Things that give me a reason to use Firefox(by priority):
1- Tabbed Browsing
2- Built-in Popup Blocking
3- Google Search supported
4- Bookmarks(favorites) Manager
5- Searching through bookmarks by Bookmarks Manager
6- Download Manager
7- Password Manager

Things That give me a reason to switch back to IE:
1- Some websites are not displayed as their are supposed to be
2- Bookmarks(Favorites) are saved on a different location and still looking for that location!!
3- Google Toolbar not supported
4- Some components are not supported natively and need plug-in downloads

Free Online Network Tools

Although most network administrators use TCP/IP tools like IPConfig, Ping, Tracert, Netstat from the command line to diagnose and fix network problems but there are occasions that using online tools can work faster and easier so it is good to know about some online TCP/IP tools:
Codeflux.com
DNSStuff
SubnetOnline
Know other online tools?

Blogger's Missing Feature: Category of Posts!

I wonder why the guys at Blogger haven't arranged for the post categories yet! You can find many questions about whether or not Blogger supports categories in different forums and you can only find one disappointing answer : "NO!"
With comments now available for posts the only thing I would like to have on my blog is to set a category for every post so that visitors can have easier and faster access to the information they are interested in.

Dr Paul Mockapetris predicts web future

"Ten years from now, we will look back at the net and think how could we have been so primitive."
"Ten years from now, we will wonder how it was so hard to find things on the network too"

And Dr Paul Mockapetris who created the Domain Name System (DNS) also predicts that there will be no need for phone numbers and only web addresses are all what we will need in future to communicate:
Net pioneer predicts web future

Free Windows RSS Feed Readers / News Aggregators

After trying out a couple of Feed Readers, now I am taking up SharpReader. Among all free news aggregators I found this one simple and easy to organize.
You can find a list of some free news aggregators here:
Top Free Windows RSS Feed Readers / News Aggregators

Yahoo is catching up with Gmail!

With 100MB of email storage, email search and auto complete feature Yahoo is trying to catch up with Gmail! 100MB of storage will be satisfactory for many users especially those using yahoo's messenger. Google has definitely seen and planned for competitors before its Gmail service announcement and we should expect something great from gmail soon. I prefer to have a Gmail notifier integrated into google's toolbar.

Spyware Explained

You should get acquainted with these evils behind the scene and know the symptoms and a couple of tricks to protect your PC from them:
Spyware Explained