Blogspot-Airtel Problem: Our Analysis

There have been lot of news about Airtel blocking blogspot today.

Well, did they really blocked it?

It’s very hard to give a direct answer to that. Firstly, I believe that Airtel must have not intentionally blocked whole blogspot.com domain name (well they are a big ISP, and I don’t think they will go that kidish!).

What could be problem?
To understand that – let’s break Internet connection into parts as per TCP/IP model

1. Physical layer + Data Link layer on bottom most

2. Network layer – DNS, Internet routing, BGP stuff

3. Transport + Application layer – web browsers, scripting, web servers, data rendering etc

Well – Physical and data link layer were not really issues – since people who were having issues must be on a system “connected” to Internet, and same with Google’s Indian mirrors (which are usually on datacenter with redundant physical links)

Next, we see #2 Network layer – yes there can be issues here. And since people were not able to open website at all, rather then getting error 404, 500 or say a broken site – there was not really issue with Transport + Application layer.

So what can be possible issues at Network layer?

Broadly speaking – it consists of two parts – DNS and Internet routing.

DNS, as I explain is last post simple resolves www.blogspot.com into IP address. I have seen a few traceroutes on Internet – and they are all timing out after a certain IP address. From that it clearly seems issue was not on Airtel’s DNS servers. If it was issue at DNS servers – then would be getting – “Name not found” error in web browser, rather then “request timed out”.

This was surely issue which we can say under “Internet routing”. That is – when you get IP address of www.blogspot.com – next, you try to connect to that machine to create a “socket connection”.

In order to find the “Physical network location” of server, ISP’s core routers use protocol called BGP – Border Gateway Protocol. This helps in creating a “path” between your system and data packets flows above it.

Right now it seems like issue is resolved. Well here’s one traceroute from popular website – IBN Live

So, we see that things started timing out at 7th hop. Last hop which responded was node with IP address – 203.101.83.197 Well, this IP address belongs to Autonomous System 9498 which is of Airtel. This means till hop 6th we were still on Airtel’s network.

Next, here’s one of traceroute taken at evening when blogspot.com was working fine.

If you observe, hop 5th here is same as hop 6th in last traceroute which was last node which responded – 203.101.83.197

In this working scenario – we see two hops are:203.101.100.210 & 72.14.216.229

First IP belongs again to Airtel, and next one is of ASN 15169 – belonging to Google. So clearly on 7th hop we are on Google’s network.With that all we can say is – there was certainly problem between either of two networks – Airtel or Google. The point from where they “peer” that is “interconnect” seems to be not available during daytime.

From traceroutes we can’t directly predict if it was just Airtel’s network or Google’s network or could be a router inside Google’s datacenter which links with Airtel’s domestic backbone. It can be glitch on BGP routers of Airtel or Google (in case of Google – the one which is specifically used in link with Airtel) as people on BSNL didn’t reported any such case.

If you are still having trouble in accessing blogspot.com – please do send us traceroutes and we would be more then happy to investigate further.

To do a traceroute on windows machine, just click on Start > run > (enter) cmd.exe
Next, in command prompt type – tracert blogspot.com and then send us the screenshot.

About the author:

Anurag is a Student and a part time network admin at dito.

He is all around network related technologies like DNS, Internet routing, servers, connectivity etc. He is also one of Power Posters at Official Google Apps forum and is involved in deployment of Google Apps.

Anurag is doing bachelors in Information & Technology from a State college in Haryana.

Ganesh February 14, 2011 at 7:23 pm

My friend has faced this issue to!! So i found out and asked him call and shout at airtel customer care!

Hari K T February 14, 2011 at 5:10 pm

@Anurag Bhatia
That was an mtr for my website. I will do the traceroute for google.com, blogger.com and upload . But for everything its the same . And the fun is they say its due to issue with OS .

Thanks

ARJUN CHANDRASHEKAR February 14, 2011 at 10:10 am

@yeshwanth
And That’s Not all Airtel is Not Maintaing it’s Servers Properly That’s Why there was a Problem in VoIP of Airtel

yeshwanth February 14, 2011 at 7:37 am

i dont have any problem with bsnl also, and idea (connected internet to mobile), i think, some thing gone errors with network layer in airtel, airtel are have their own server, that y they have a problem.

Anurag Bhatia February 13, 2011 at 8:41 pm

@Abhijit S

Very interesting. I heard of problems ONLY on Airtel’s network. Remember Tata uses totally different route for connecting to network. I found it’s only BSNL which uses same route as it goes to Google’s servers via Tata’s VSNL.

Infact BSNL is taking most of it’s (International) bandwidth from Tata communications. BSNL, Tata Comm, TTSL, Sify, and many more players use Tata’s network for reaching US – where most of datacenters are located.

Anurag Bhatia February 13, 2011 at 8:37 pm

@varun

Do a continuous ping to one of those “not-opening” sites for 10mins, and then a traceroute and paste result here.

Anurag Bhatia February 13, 2011 at 8:36 pm

Hari K T :
I am having a similar issue with BSNL EVDO. The mtr command’s screenshot is here . http://twitpic.com/3oj6nj
I feel BSNL too is having issues. But in landline its not having any issues with traceroute and all. Let me know if anything more is needed.
Thanks

Are you sure you did traceroute to Blogspot.com? It seems like you are going to some totally different server – server1.rackloop.com

?

varun February 13, 2011 at 8:02 pm

Few websites not opening with BSNL 3g. some sites need refresh 3-5 times to load properly. I am facing this problem since last 19 days(3G activated on Jan 25th).Downloading is perfect but browsing…..Horribleeeeee….

Anurag Bhatia February 13, 2011 at 7:29 pm

Kishor :
wow!!!…interesting tech info.
@Anurag,
Thanx alot dear. Nice to see such interesting articles in TT. We are eagerly waiting for your next post.

Thanks Kishor and everyone else

Kishor February 13, 2011 at 5:30 pm

wow!!!…interesting tech info.
@Anurag,
Thanx alot dear. Nice to see such interesting articles in TT. We are eagerly waiting for your next post.

Abhijit S February 13, 2011 at 5:12 pm

@Anurag

Even i noticed that some of domains pointing to blogspot.com are not working most of the time. This issue is with TATA communications too.

I will send a tracert from TATA communications static IP the day after as i use it in office.

Now i am wondering, it it ISP’s problem or Google’s problem ?

Any idea ?

Hari K T February 13, 2011 at 4:09 pm

I am having a similar issue with BSNL EVDO. The mtr command’s screenshot is here . http://twitpic.com/3oj6nj
I feel BSNL too is having issues. But in landline its not having any issues with traceroute and all. Let me know if anything more is needed.

mark February 13, 2011 at 11:36 am

well, thats an interesting tech how things work… may be you will share on 3g and other wireless connectivity too.

Ankur Mhatre February 13, 2011 at 9:51 am

May be due to dns fault

Sujith February 13, 2011 at 9:09 am

Some months back the same problem was with Aircel.we were not able to open any website which ends with blogspot.com
but we were able to visit our dashboard and add new posts to our blog.But using Aircel not able to preview it or visit the site.

Kaushik Roy February 13, 2011 at 1:25 am