[nos-bbs] rip broadcasts in jnos

[Maiko Langelaar (Personal)]

This is just additional information, mildly related to home setups, but
I might as well add it in for documentation purposes. I run one JNOS
development system on a linode VM, so I have the luxury of a fixed
IP address, and I get ipv6 'for nothing extra' to play with as well.

This will still work with a dynamic IP address, but like people have eluded
to, you better make sure your gateway IP address is kept as up to date
as possible, if you're lucky, your dynamic might stick around for a while.

My JNOS is setup to do all the encap (via RIP broadcasts), so my gateways
entry points to the JNOS SIDE of the tun interface between JNOS and linux.

In order for linux to be able to route IP IP (protocol 4) to JNOS, I use 
this
entry below in my iptables startup script :

   ## 02Oct2017, Forgot to enable IPV4 forwarding !
    echo 1 > /proc/sys/net/ipv4/ip_forward

   ## 24Jul2017, This seems to work for majority of AMPRnet connectivity
    /usr/sbin/iptables -t nat -A PREROUTING -i eth0 -p 4 -j DNAT \
      --to-destination 192.168.200.201

    /usr/sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

That's an older way to do it, I have yet to look at nftables and so on.

Then of course, the JNOS side commands for RIP would be these :

   # a 'new' command - allow jnos to recognize multicast used in RIP update
    ip upstairs 224.0.0.9

   # purging of old routes depends very much on route expiry. I am
   # experimenting with 1/2 day for my route lifes
    rip ttl 43200

   # start the rip client
    start rip

   # accept RIP update from the AMPRgw system
    rip accept 44.0.0.1

   # uncomment this entry to debug or trace the RIP update process
   # rip trace 9 rip.log

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Maiko / VE4KLM