the problem is fixed with a friends help. Thanks to him.
Pluto works together with a standalone PC without a router.
This is the only change in the config. txt.
ipaddr_eth = 192.168.1.205
netmask_eth = 255.255.255.0
The IP is just an example. Assign a fixed IP in the host with the same subdomain and subnetmask.
Additional type Pluto's IP in the standard gateway mask.
when edit the config and restart the Pluto the changes are gone?
What do you mean by 'the same subdomain' please?
What am I missing please?