I'm using a web application known as IOU-Web. This application is used to execute CISCO IOS software in a browser. Here is what topology looks like
And here is what interfaces config snap
Now the idea is that R1 should be able to access the host machine which is my Laptop (Ubuntu-12.04). When I ping from my laptop terminal to R1, R1 successfully caches the ARP entry against my laptop Eth1 MAC. However, Ubuntu does not cache / update the MAC address of R1. I used tcpdump to inspect the traffic and interestingly, I can see the ARP reply from R1. Then I also tried static binding of R1-MAC in the Ubuntu ARP table, but even after that I was unable to ping R1. Though a debug on R1 shows that it did send reply to echo requests (ping).
TL;DR My Ubuntu machine is not updating its ARP-cache even though ARP replies are being recived.
Earlier I had done some googling and stumbled upon a post where it mentioned a similar issue being resolved by disabling "Reverse Path Forwarding Kernel Parameter". That kinda made sense and I tried that solution as well by disabling "RP_Filter" using the command
sudo sh -c 'echo 0 > /proc/sys/net/ipv4/conf/all/rp_filter'
and
sudo sh -c 'echo 0 > /proc/sys/net/ipv4/conf/eth1/rp_filter'
But that didn't help either. Can someone please give some tips on possible course of action to resolve this issue?
