Bash-2

Earlier this month Dyn started with it’s Indian PoP. I came across news from Dyn’s blog post. It’s very good to see first Amazon AWS and now Dyn in India. With a warm welcome to Dyn let’s look at their Indian deployment.

Dyn using AS33517 which seems to be having upstream from Tata-VSNL AS4755 and Airtel AS9498. 

Dyn seems to be announcing 103.11.203.0/24 to both networks in Mumbai to transit. There are routes in global IPv4 routing table which show Tata & Airtel as transit for Dyn. It cannot be just a /24. I am sure there are more prefixes which are very likely locally announced. Since deployment is at Mumbai, let’s try to look at NIXI Mumbai for prefixes.We can see Tata AS4755 is using 218.100.48.85 and Airtel is using 218.100.48.86 from NIXI route server at Mumbai with simple “sh ip bgp sum” query. I tried taking entire table of Tata as well as of Airtel from NIXI route server but not able to get it beyond few thousand routes. 

Whenever I see a new unknown IP range, it gets hard to find exact source of that IP within command shell. Recently, I found a very interesting source of that information from Team Cymru.

I figured out (with a friend’s help) that using their whois server - v4.whois.cymru.com one can actually grab limited information as required. 

E.g

anurag@laptop:~$ whois -h v4.whois.cymru.com "  -v 8.8.8.8"
AS      | IP               | BGP Prefix          | CC | Registry | Allocated  | AS Name

15169   | 8.8.8.8          | 8.8.8.0/24          | US | arin     | 1992-12-01 | GOOGLE - Google Inc.

As we can see -v gives all possible information. All I needed was AS number, AS Name, BGP Prefix, Country code - this gives enough information for an IP address. Thus command turns out to be with -c & -p.