Replace existing router with linux server
Posted on 2011-09-02
I need some help from someone with Cisco IOS expertise and linux configuration expertise. I have to replace a cisco 3800 router with a linux server which will do the same functions that the router was doing. Router is terminating GRE-IPSEC tunnels as well as normal routing and some firewalling. I can do the general config on the linux but there are tweaks and tuning in the Cisco IOS that was done for performance reasons and I need help translating those tweaks to the linux configuration.
For example, in the router we used a route map to turn off the Don't Fragment bit...
So on the corresponding physical interface I have:
ip policy route-map DF
whereas the route map is...
route-map DF permit 10
match ip address 111
set ip df 0
access-list 111 permit tcp any <<internal user IPs>>
Another example for the tunnel interface...
ip add 10.1.1.2 255.255.255.0
ip mtu 1300
ip tcp adjust-mss 1200 ---> what is it in linux?
tun sou FastEthernet0/0
tun dest 172.21.2.36
tunnel path-mtu-discovery ---> what in linux?
crypto ipsec df-bit clear ---> what in linux?
Another example, we had to increase the maximum number of datagrams that can be reassembled...
ip virtual-reassembly max-reassemblies 32
There are more but these three are the most pressing. Anyone well versed in Cisco IOS and linux that could lend a hand?