On Tue, Mar 10, 2020 at 08:45:17PM +0000, Björn Johannesson wrote: > Hello. > > I'm trying to connect two machines via slip(4) and then get communication > going outside those two. > One of the machines have a NIC and I wan't to get the machine behind that one > to reach outside. > I have done this once long ago and I had jotted down these notes: > https://pastebin.com/UK43aV5x > I'm trying to get this working on again now. IP's have changed ofc. > > On the machine w/o NIC I do: > ifconfig sl0 create > slattach -s 115200 /dev/tty00 > ifconfig sl0 inet 192.168.0.51 192.168.0.50 > route add default 192.168.0.50 > > On the machine with NIC: > ifconfig sl0 create > slattach -s 115200 /dev/tty00 > ifconfig sl0 inet 192.168.0.50 192.168.0.51 > arp -s 192.168.0.51 6c:3b:e5:1f:98:d8 pub proxy > sysctl -w net.inet.ip.forwarding=1 > (The real NIC on this machine has ip 192.168.0.114 netmask ffffff00)
6c:3b:e5:1f:98:d8 is the mac address of your real nic, right ? > > The two machines communicate fine with each other - however the forwarding > part does not. > 192.168.0.51 cannot communicate past .0.50 and cannot be reached from outside > .0.50. > There is also a _significant_ delay when communicating from .51 to .50 after > adding the "route" command. > If I ping .50 from .51 it takes many seconds (>10) before it starts sending > packets. Probably a DNS-related timeout. You could try running tcpdump on the real NIC and watch for traffic from/to 192.168.0.51. Also watch for ARP traffic. I've used a very similar setup with netbsd-8, it works. I'm not use I tried with -9 yet. Also in my notes I see that I set the sl0 MTU to 1500, maybe because by default the MTU is too low. -- Manuel Bouyer <[email protected]> NetBSD: 26 ans d'experience feront toujours la difference --
