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Tag Archives: networking

Split Routing with OpenVPN

My place of work has installed a VPN that moderates our access to the server network using the OpenVPN protocol. This is a good thing, but in its default configuration it would send all traffic — even that not destined for the machine room network — through the VPN. Since most of what I do doesn’t involve servers in the machine room, I wanted to change the configuration of the OpenVPN client to only send the machine room traffic through the VPN and everything else through the (original) default gateway. As it turns out, this involves tweaking the routing tables.

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2010 02 15 Comments (0)

On the Internet, How Do You Know If You Are Talking to a Dog?

Illustration of a dog, sitting at a computer terminal, talking to another dog. Includes caption: “On the Internet, nobody knows you’re a dog.”Published in The New Yorker July 5, 1993.
Image from The Cartoon Bank

The famous 1993 cartoon from The New Yorker has the caption “On the Internet, nobody knows you’re a dog.” The question at the moment is: when you’re on the internet, how do you know you are not talking to a dog? When you ask to connect to a remote service, you expect to connect to that remote service. You probably don’t even think about the possibility that “myspace.com” might not be “myspace.com”. But what if you couldn’t rely on that? How about “mybank.com”? Believe it or not, you may exist in such a world today. Last week, US-CERT issued a “Vulnerability Note” on Multiple DNS implementations vulnerable to cache poisoning. What does that mean? Read on…

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2008 07 15 Comments (4)

Vint Cerf on the Origins of 32-bit IP Addressing

Via a weekly wrap-up post by Dion Almaer on the Google Code Blog comes mention of a Google Tech Talk video from their IPv6 Conference 2008. It is a panel discussion called “What will the IPv6 Internet look like?” and it offers insight into the difficulties of transitioning to the next generation IP transport protocol. Although it has been years since I’ve seen the business end of managing an actual IP network, I found the discussion a fascinating look at the issues that are ahead of network engineers and device manufacturers around the world.

This is a preview of Vint Cerf on the Origins of 32-bit IP Addressing. Read the full post (462 words, 1:51 minutes estimated reading time)
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2008 03 07 Comments (3)

Note to Future Self: Use `ssh -D` to bypass annoying interception proxies

Dear future self,

If you are reading this, you are remembering a time when you ran into a really nasty interception proxy1 and you are looking for a way around it. Do you remember when you were sitting in the Denver International Airport using their free wireless service? And remember how it inserted advertising banners in HTML frames at the top of random web pages as you surfed?

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2008 02 18 Comments (18)

Getting Around Drupal’s Prohibition of @ Characters in User Ids

A while back we created an LDAP directory to consolidate account information for various back-room services, and when we created it we decided to use the individual’s e-mail address as the account identifier (uid in LDAP-speak). It seemed like the logical thing to do — it is something that the user knows and it is a cheap and easy way to assume that the account identifiers will be unique. This is not uncommon for many internet services, of course.

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2007 01 19 Comments (0)

IAB to Address Concerns About Internet Routing Scalability

An e-mail from Leslie Daigle, chair of the Internet Architecture Board, crossed my inbox tonight through the IETF-announce list (excerpted below) that brought back memories of the mid-90s and the Internet growth explosion that spurred the deployment of NAT (Network Address Translation) devices, the shift in large scale Internet routing from a “Classful” system to a “Classless” system (called Classless Inter-Domain Routing, or CIDR), and fueled the (relatively) quick development of IPv6. The conditions are somewhat different from decades ago, but some of the solutions are the same. If you are interested in how the guts of the internet work, read on. I’ve expanded organizational acronyms and linked to documents and other helpful bits; this stuff is fascinating (in the same way that one can walk into the machine room and gaze in amazement at all of the lights blinking in just the right way to tells you it is all working together just fine).

This is a preview of IAB to Address Concerns About Internet Routing Scalability. Read the full post (489 words, 1:57 minutes estimated reading time)
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2006 12 20 Comments (1)
From the Disruptive Library Technology Jester (http://dltj.org/), printed on Wednesday the 17th of March 2010 at 8:45:24 PM EDT (-0400). The URL to this page is http://dltj.org/tag/networking/

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