Resume and bio of the author Couple of articles related to my hobby - robotics
My impressions about immigration to Australia. In Russian only. Recipes for everyday problems solving
Linux-related posts Windows-related posts
Software-related posts A lot of info about hardware
Different tools you might find useful Posts about various web technologies
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Andrey Mikhalchuk’s Blog

Technoblog about life

Apr 3, 2013 How to Map Ports in Windows

Port mapping is a great feature that allows you to make almost any remote network service to work like it is running on your computer. Most people use specialized software to make it work, however there is a built-it Windows command that allows you to do exactly the same thing. Fire up windows command shell (Start->Run->cmd) and run this command:

Dec 9, 2012 Verizon blocks port 25. Wow!

I have just spent several hours narrowing down the problem, 30 useless minutes with someone in Verizon chat support and 20 min on the phone line. All the time was wasted just to find out that Verizon is blocking outgoing connections to port 25. That basically means that you can’t use your own mail servers for sending emails using plain (E)SMTP. The only unblocked server is

In fact many ISPs do that in order to fight spamming, but after years of not having this problem with Comcast that was kind of unpleasant surprise.

In my case I needed the external mail server for my webcams (I have whole bunch of them providing security at my place). Fortunately Foscams I use support alternative ports, so I just opened my mail server on an alternative port and reconfigured the webcams. If you’re using postfix, just drop this into /etc/
inet n – n – – smtpd

restart the postfix, patch your firewall if necessary

Oct 23, 2008 How to add serial interface to WRT54GL router

If you decided to mod your wrt54gl router and turn it into one of the most capable routers for soho network, probably the first mod you should start with is adding serial interface to it. Why? Because when you do the other mods (like adding SD reader, turning into robot, adding leds etc) you definitely send the router into the brick state. And the best way to unbrick it is to look at the router’s console output. The entire operation is very easy and should not take longer then 1 hour. Here is how to do this:

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