Networking

Yesterday I spent sometime in answering questions on Google Apps forum. I really love this forum as I used to post a lot there. These days I don’t get much time for forum involvement.

Anyways, yesterday I came across very interesting post from a user named Sandip. He got an error from Google’s DNS checking in the Google Apps Toolbox.

Error:

Presence of mail server on A record of your domain can lead to subtle and hard-to-debug problems with mails ‘accidentally’ missing in case of DNS problems. You can check this problem yourself by typing

I was just working (and playing music!) and realized that “Movie player” package given on default Ubuntu installation isn’t of much use. 

Decided to uninstall it, next needed arping for some test and installed it (via default debian repository). Something crazy happened here. I opened something on personal server and it gave DNS error. I shot couple of digs from terminal and all timed it. I was scared to hell thinking of DNS failure on personal domain which is very very unlikely since I am using multiple DNS providers and close to a dozen of servers serving DNS zone. 

Yesterday I had a discussion with a friend from Airtel after long time. For some strange reason discussion topic was changed to old statements from Bharti Airtel’s executives that companies like Google, Facebook, Yahoo etc should pay to ISPs like Airtel for “data interconnection”. The argument goes more for Google then any other company. Statements from Airtel can be found here and here. 

The argument?

Companies like Airtel who have built a “physical infrastructure” feel that companies like Google should pay to them since they are putting so much of traffic on their networks. Airtel feels that services like YouTube take significant amount of bandwidth and thus requires and infrastructure from core, middle mile to edge part of network and all that needs significant investment. Similarly there was another argument from Mr Sunil Mittal about fact that Facebook is enjoying on top of infrastructure which ISPs like Airtel have created.

Quick analysis of BSNL-Level3 bad routing issue

I can see BSNL having pretty high latency again with most of Europe again. It seems like they are using Level3 Communications AS 3356 along with Tata-VSNL for upstream. With Level3 transit BSNL has badly screwed up reverse path causing very high latency and awful bandwidth.

anurag@laptop:~$ ping server7 -c 5
PING server7.anuragbhatia.com (178.238.225.247) 56(84) bytes of data.
64 bytes from server7.anuragbhatia.com (178.238.225.247): icmp_req=1 ttl=52 time=320 ms
64 bytes from server7.anuragbhatia.com (178.238.225.247): icmp_req=2 ttl=52 time=320 ms
64 bytes from server7.anuragbhatia.com (178.238.225.247): icmp_req=3 ttl=52 time=319 ms
64 bytes from server7.anuragbhatia.com (178.238.225.247): icmp_req=4 ttl=52 time=327 ms
64 bytes from server7.anuragbhatia.com (178.238.225.247): icmp_req=5 ttl=52 time=320 ms
--- server7.anuragbhatia.com ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4004ms
rtt min/avg/max/mdev = 319.880/**321.765**/327.384/2.828 ms
anurag@laptop:~$

Expected latency values here should be around 150ms. A packet should not take more then 150ms round trip between Radaur, Haryana to Munich located server.

Boring exam days, anyways time for a quick blog post to keep taste in life. :)

One of my good friend informed me about eNom DNS servers failing randomly. He gave clothdiaperrevival.com as sample domain name for testing.

Quick Check from my home connection:

anurag@laptop ~ $ dig clothdiaperrevival.com a @dns1.name-services.com +short  
216.239.32.21  
216.239.34.21  
216.239.36.21  
216.239.38.21

anurag@laptop ~ $ dig clothdiaperrevival.com a @dns2.name-services.com +short  
216.239.36.21  
216.239.32.21  
216.239.38.21  
216.239.34.21

anurag@laptop ~ $ dig clothdiaperrevival.com a @dns3.name-services.com +short  
216.239.38.21  
216.239.34.21  
216.239.32.21  
216.239.36.21

anurag@laptop ~ $ dig clothdiaperrevival.com a @dns4.name-services.com +short  
216.239.32.21  
216.239.38.21  
216.239.34.21  
216.239.36.21

anurag@laptop ~ $ dig clothdiaperrevival.com a @dns5.name-services.com +short  
216.239.32.21  
216.239.34.21  
216.239.36.21  
216.239.38.21

Next, checking from my EU located server:

anurag@server7:~$ dig clothdiaperrevival.com a @dns1.name-services.com +short  
216.239.32.21  
216.239.34.21  
216.239.36.21  
216.239.38.21

anurag@server7:~$ dig clothdiaperrevival.com a @dns2.name-services.com +short

anurag@server7:~$ dig clothdiaperrevival.com a @dns3.name-services.com +short  
216.239.36.21  
216.239.38.21  
216.239.32.21  
216.239.34.21

anurag@server7:~$ dig clothdiaperrevival.com a @dns4.name-services.com +short  
216.239.32.21  
216.239.38.21  
216.239.36.21  
216.239.34.21

anurag@server7:~$ dig clothdiaperrevival.com a @dns5.name-services.com +short  
216.239.32.21  
216.239.34.21  
216.239.36.21  
216.239.38.21

dns2.name-services.com is failing when reached my EU based server.