Subnetting IPv6 sounds very complex but to be true - it is very easy! All you need to do is to understand basics of IPv6 addressesing - how an address is formed and how to efficiently use CIDR notation. Firstly how an IPv6 address looks like? (good to clear fundamentals first!) An IPv6 address has 8 sections seprated by coloums and each sections has carries 4 hexadecimal digits. So an IPv6 address is something like: xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx - Each x can have a hexa decimal value i.

In last few days, I have been pushing discussion on APNIC & NANOG mailing lists about poor DNS infrastructure in India. Thought to put a quick blog post on the issue. So what’s exactly wrong? To understand what’s wrong, let’s understand how DNS works at core level. DNS relies on a hierarchy model with . (dot) on top which is Root and TLD i.e Top Level Domains below Root, which further follow 2nd level domains which are popularly domain names we use.

I am blogging after quite a few days. Spent bit of time at events like APRICOT 2012 - New Delhi, followed by (unexpected) college start (on time) with heavy fine! Overall time is moving fast. Last week TeamARIN posted a guest blog post from me on DNS in case of IPv6. Apart from that I was excited with small article from RIPE NCC about K-root server connectivity issue as reported by me on mailing list.

Few days back I mentioned how reverse DNS setup of Airtel was incorrect. Sad to say it has not been fixed yet. In meanwhile I was looking at domain name - airtel.in the main domain which runs website for Bharti Airtel’s Indian operations. I am little surprised to find that DNS server of airtel.in are failing randomly! Problem: airtel.in uses 4 DNS servers from Mantra Online - a small ISP which Bharti took over years back.

Yesterday I came across a very interesting case of network hijacking of an ISP from wrong BGP announcements by another network. This issue was reported to NANOG mailing list. Issue was reported by Kevin, Senior Engineer at Altus Communications (AS11325). Problem was that SBJ Media LLC (AS33611) was making a /24 block announcement for specific slices of Altus - 208.110.48.0/20, 63.246.112.0/20, and 68.66.112.0/20 which are allocated to Altus Communications (as per ARIN whois).