In order to set a ppp connection as a normal user I have had myself in the dip group (for pppd) and in dialout for my /dev/ttySx.
Is this safe ? Now it works but I obtain this $ wvdial provider ... --> PPP negotiation detected. --> Warning: Could not modify /etc/ppp/pap-secrets: Permission denied --> --> PAP (Password Authentication Protocol) may be flaky. --> Warning: Could not modify /etc/ppp/chap-secrets: Permission denied --> --> CHAP (Challenge Handshake) may be flaky. --> Starting pppd at Tue Jan 4 23:37:56 2000 But the files are in the group root. Should I changed something or not ? Christophe