Re: Route from LAN to Hercules

Typically this problem is a missing route from the LAN device to the
Hercules guest IP address via the Hercules host IP address.

This is not a server problem but a device problem.  Packets require
routes on both ends of the connection to make it.  In  this case the IP
addresses involved are the Hercules guest (not the host) and LAN device
with the telnet client.

There are numerous variations on this theme, but it boils down to the
same issue: getting the IP packets from the LAN devise to the Hercules
guest.

Harold Grovesteen

On Sun, 2020-01-19 at 21:25 +0700, Robin Atwood [email protected]
[hercules-390] wrote:
> After a 10 years long hiatus I am messing around with Hercules again.
> I am
> running Herc on a headless server and want to run x3270/telnet/ssh
> from
> a laptop on the LAN. The server is 192.168.100.2 and the Herc
> guest has an LCS device with address 192.169.100.12. So on the server
> the routes are:
> 
> # route -n
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags Metric
> Ref    Use Iface
> 0.0.0.0         192.168.100.1   0.0.0.0         UG    3      0       
>  0 enp5s0
> 127.0.0.0       127.0.0.1       255.0.0.0       UG    0      0       
>  0 lo
> 192.168.100.0   0.0.0.0         255.255.255.0   U     0      0       
>  0 enp5s0
> 192.168.100.12  0.0.0.0         255.255.255.255
> UH    0      0        0 tap0
> 
> The server has an iptables forwarding rule:
> ACCEPT     tcp  --  0.0.0.0/0            192.168.100.12       tcp
> dpt:23
> 
> If I shell into the server I can use telnet to get a session with the
> guest. On the laptop I created a route:
> # route -n
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags Metric
> Ref    Use Iface
> 0.0.0.0         192.168.100.1   0.0.0.0         UG    20100  0       
>  0 enp0s25
> 127.0.0.0       127.0.0.1       255.0.0.0       UG    0      0       
>  0 lo
> 192.168.100.0   0.0.0.0         255.255.255.0   U     100    0       
>  0 enp0s25
> 192.168.100.12  192.168.100.2   255.255.255.255
> UGH   0      0        0 enp0s25
> 
> and I can ping and traceroute the guest OS:
> 
> # traceroute -n 192.168.100.12
> traceroute to 192.168.100.12 (192.168.100.12), 30 hops max, 60 byte
> packets
>  1  192.168.100.2  0.326 ms  0.295 ms  0.263 ms
>  2  192.168.100.12  0.624 ms  0.956 ms  1.736 ms
> 
> But when I try x3270 or telnet the connection just hangs. What have I
> missed out?
> 
> Thanks
> Robin