[Nix-dev] "pppd is unable to open the /etc/ppp device"

[Paul Dufresne]

I did not really test NixOS lately, but normaly /etc/ppp is rather
where to find configuration files. The device is usualy /dev/ttyS0
(for the first serial RS232-C connector) or /dev/ttyS1 (for the second
one). Or even /dev/ttyS2 or /dev/ttyS3 for the third and fourth in
some cases (mostly internal one).