I have been using OpenVPN from quite sometime and very much like it. Earlier I was running OpenVPN client on TP Link 1043nd router and that worked great. But recently I switched home routing to Microtik Map2N which has much better VLAN & IPv6 support. Since then I had trouble in getting VPN back live. I can always use VPN client on laptop but that’s ugly for daily use specially when this is my primary work location!
Enjoyed ISC’s presentation about their analysis of F root server (one 13 root DNS servers which power the Internet) about anycast performance gloablly for 192.5.5.0/24 announced (and anycasted) by AS3557 (ISC). This was presentation at UKNOF 32.
Embedded presentation below (or click here to watch on YouTube directly)
K root in Noida seems to be not getting enough traffic from quite sometime and connectivity does seems bit broken. This is a blog post following up to Dyn’s excellent and detailed post about how TIC leaked the world famous 193.0.14.0/24 address space used by AS25152. It was good to read this post from RIPE NCC written by my friend Emile (and thanks to him for crediting me to signal about traffic hitting outside!)
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?
All above tells nothing but ways in which BSNL is 100% screwed up for now. I don’t expect it to ever pick up again. Politically, technically, and fundamentally it’s a mess. I became BSNL broadband user in 2008 and it has been over 7 years of (painful and terrible) experience with them. As a company which put so much of infrastructure to connect India worked extremely hard to do as many stupid things as possible. For me trouble remained that in my city they were only wired telecom provider for retail services. Last month I got a long haul circuit from Airtel (provisioned on fiber) between my city and a friend’s ISP PoP for 10Mbps bandwidth. Circuit is delivered at a Airtel BTS site location (slightly away from my home) and I have installed Microtik SXT Lite 5’s shooting link from there to my home (around 1km link with clear LoS). This is a usual long range fixed wireless RF link over un-licensed 5.8Ghz band. (Thankyou govt. of India for delicensing it in 2007 and making available for public use). Thanks to companies like Microtik and Ubiquiti for opening up world of good fixed wireless radios and antennas which really work great and are available for quite good prices. I got pair of SXT Lite5’s from Amazon.in at 7700 INR (~$116). Fortunately BTS site has a private WISP tower and the owner of tower agreed to let me use his tower for my radio for reasonable price.
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. You can find similar concept for CentOS. Say you have a router on IP 10.10.10.1 and server on IP 10.10.10.2 on a /24 (255.255.255.0) subnet. Assming that entire 10.10.10.0/24 is available for server’s connectivity. Setup would be like: 
Configuration so far is super simple. You have got 10.10.10.1 placed on R1’s interface (g1/0) which connects to server01 and server01 has 10.10.10.2.
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. With Google only key difference I noted is that my TCP session to Google’s services is terminating at Mumbai and not Delhi anymore. First and formost, I did trace to spectranet.in (which is last company I was working for) to see how is my latency with server hosting it:
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.e for packets to reach from User 1 to User 2, we need to ensure that User 1 has default route towards R1, knows that User-2’s IP is behind R3 which is reachable via R2. So path User 1 > R1 > R2 > R3 > User 2 comes up. And same for User 2 > R3 > R2 > R1 > User 1 as return path. Now e.g IP pool for User-1 is 192.168.1.0/24 and is using 192.168.1.2 out of it while IP pool for User-2 is 192.168.2.0/24 and is using 192.168.2.2 out of it.
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). In start I felt it to be usual crappy 5G talk but later realized it was much more interesting. I loved the idea “Have 2Mbps everywhere static broadband and not some absurd number on mobile wireless broadband as we hear in case of 3G/4G. Although 2Mbps now is much slower and I would rather suggest that we target for 10Mbps everywhere (something which can be supported by copper/coax/fiber hybrid) but anyways it was nice refreshing talk. His thoughts were interesting but mostly impractical since had high dependence on useless project like NOFN. For the next part, we had a nice theme of keeping network simple which everyone kind of liked. Simplicity in Network Design & Deployments by Dany Pinto (from Colt) and Unified Forwarding with Segment Routing by Mohan Nanduri (from Microsoft Azure Cloud WAN team) were part of that. Santanu Dasgupta gave a presentation about Challenges of L2NID based Metro-E Architecture for vCPE/NFV Deployments and kind of confused everyone. :P
One of very cool features of IPv6 is link-local address which stays local to a given link. For this fe80::/10 is reserved. A /10 is a huge amount of address space in IPv6 (and in IPv4 too :) ). This means from fe80:0000:0000:0000:0000:0000:0000:0000 to febf:ffff:ffff:ffff:ffff:ffff:ffff:ffff.
Since by design link-local address stays local, the address configured on the upstream/gateway router can be kept same for ease of use and comfort. This wasn’t the case of IPv4 where each VLAN/layer 2 domain had it’s own gateway. So e.g if you have two VLANs or interfaces say: Gi1/0 and Gi2/0. You decide to use 10.100.100.0/30 on Gi1/0 and 10.100.100.4/30 on Gi2/0.
Out in Mumbai to attend SANOG 26.
Meet and greet if you are attending as well or around in Mumbai. :)