A blog post dedicated to BSNL AS9829. It just tried so hard to become as irrelevant as it can from everyone’s life (and that doesn’t excludes me now). So what really is BSNL btw? A Govt of India telco sitting at a extensive fiber of over 600,000 Kms across the country (staying just unused and unavailable for anyone’s use!) A telco which has an extensive last mile copper (which is very poorly maintained and barely works!

One of things which people often asked me around in past was on how to have multiple IPs on Linux machine under various circumstances. I know there are ton of blog posts about this but very few explain how it works and possible options under different use cases etc. I will share router side and server side config with focus on how it should be done from server end. Assuming server side config to be for Ubuntu/Debian.

Today I met a good friend and he has recently moved back into Rohtak (like me!) and was crying over BSNL’s issues. He has issues of unstable DSL due to last mile and I told him that even if last mile works well, BSNL still has got ton of issues with their IP backbone traffic. It’s Sunday late night out here in India and I am having really pathetic connectivity with just everywhere except Google.

BCP38 - also known as “Network Ingress Filtering” is concept where we filter incoming packets from end customers and allow packets ONLY from IP’s assigned to them. Before going to BCP38, let’s first understand how packets forwarding work: Here User 1 is connected to User 2 via a series of router R1, R2 and R3. Here R1 and R3 are ISP’s edge routers while R2 is a core router. In typical way the network is setup, entire effort is given on logic of routing table i.

Just finished with SANOG 26 conference and tutorials. It went very nice. Interestingly this time conference did not start early morning like it did in SANOG 24 at Noida. It was rather late in afternoon. Also, on very good note - there were less Govt. bureaucrats to bore attendees with usual stuff they always talk about but have very little idea. One specific interesting presentation was Opportunities and Challenges for Broadband Wireless in India by Prof Abhay Karandikar (from IIT Mumbai).