Saturday, December 16, 2006

Hole Punching: To Do Or Not To Do

Hole punching technique is nothing new. It is as old as the firewalls through which it punches hole. But due to the huge popularity of Skype which does hole punching to make VoIP work even when behind firewalls and due to the apparent inability of network administrators to block them, there is a new wave of articles on this topic.

Slashdot covered one such article. After reading the comments there it became clear that many don't really understand how protocols like TCP and UDP work or why hole punching works.

Hole punching head-ache at office:
Hype is that network administrators will have a lot of headache managing the bandwidth consumed by all these p2p applications that punch holes and "illegally" transfer data. But that isn't the case in reality. Network administrators have a variety of options at their disposal. Like in case of Skype, they can always block the various Skype central site IP addresses. Also, an advanced stateful firewall like IPTables in Linux can be configured to block hole-punching. But, in some cases, hole punching applications can actually save bandwidth. If you and your colleague sitting on the other end of the office are talking to each other over skype and are on the same local network, then your traffic isn't even leaving your network! You two would be connected peer 2 peer directly. So there you go! Your network administrator should be happy!

Hole Punching at home?:
In this part of the world(India), majority ISPs like Airtel or BSNL provide public IPs for their broadband customers. So, when I'm connected to Internet at home, I've a public IP (non-static). So, there is no question of complex NAT firewalls getting in the way.(We all do have firewalls on our machines and on the router, but they are just filtering unwanted traffic and not actually doing any NAT). So, I can actually tell my firewall to allow Skype traffic bothways and no hole punching is required. Skype MAY become a super node and start using your bandwidth for routing other people's voice data. Now, if you aren't on a unlimited usage bill-plan this might hurt you. So, its best to turn off the application when you are not using it yourself.

We at pi are building an application that also does hole punching. It's more exciting than skype and has lot more functionality. Currently it is in free beta mode. Go grab it and try it for yourself.
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Tuesday, December 12, 2006

Free Google for Small Businesses!

Most people think Google is a search company! Well, yes they are a search company. But primarily they are a very good web technology company. What they do brings Internet and its way of life much closer and more easier to many people. Can you imagine that if you are a small business owner, you have quite a few things going for you because of Google. The product of theirs I'm referring to here is Google Apps for Domains.
Google Apps for Domain provides free e-mail (2GB) accounts at your domain address. This, along with the google talk messenger service at the same address, pages, and calendar make it a pretty nice offering, all for free. Also, throw in a restricted private groups at google groups beta, you have a pretty good online infra structure for your company! Very reliable, secure and free!

I just setup all this for a company called SSC Vanilla. And the handful of people at this company are already using it and seeing the benefits.

More to come later, may be.
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Friday, December 08, 2006

Google 403 Bot Error! on trying to set preferences from Firefox!

Today I searched for "form $PHP_SELF" on Google the search within Firefox. I got 10 results. I wanted more. So, I hit preferences and changed the number to 100. When I save the preferences and it gets back to the page, this is what it says!


Google
Error

We're sorry...

... but your query looks similar to automated requests from a computer virus or spyware application. To protect our users, we can't process your request right now.

We'll restore your access as quickly as possible, so try again soon. In the meantime, if you suspect that your computer or network has been infected, you might want to run a virus checker or spyware remover to make sure that your systems are free of viruses and other spurious software.

We apologize for the inconvenience, and hope we'll see you again on Google.



Then I opened google home page, went straight to preferences and changed results to 100 and then did my search. viola! everything was fine! So there was nothing inherently wrong with the query. its some bug in the way they handle redirection from preferences page after changing the results count, i guess!
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Monday, December 04, 2006

Microsoft Office 2007 First Impressions!

I just got my hands on Microsoft Office 2007. My first impression about it is very positive. Its very slick and nice. The UI is very refreshing and easy to use. And its faster and intelligent. I've tried just the Word, Excel and Powerpoint till now. Saving Powerpoint to pdf is very nice. It needs a plugin to be installed. Its not obvious why they didn't include it by default.

Although the installation took a lot of time, it was very easy and asked few questions. It detected and upgraded my Office 2003 installation.

Outlook 2007 still sucks. Nothing much different. Too slow and still hangs with IMAP over SSL.

Probably I post a more detailed review later.

Once again, Microsoft has made sure that its stronghold office presence isn't threatened by any other Free or commerical offerings.
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