Few months ago friend of mine told me about this weird DNS problem. According to him only root can browser Internet but normal users are not allowed to browser Internet or dial out. I told him how how to setup system so that normal user can dial out by adding user to dialout and dip group under Debian Linux. But still he had same problem “Root can browser Internet and normal user cannnot”. So y'day I paid visit to his house.
He uses dial up account from RIL (reliance dial up over CDMA phones). RIL provided them scripts to connect system via pppd and chat programs. Problem was one of the script or pppd itself was creating new DNS file at /etc/resolve.conf with read only permission to root user only. So only root can get address of nameserver. I quickly fixed this by modifying his /etc/ppp/options and /etc/ppp/ip-up.d/0dns-up files.
It was really weird why scripts setup read only permission on /etc/resolve.conf. Must be a BUG in ISP script and very few people using it under Linux. And those using they must be running system as root user. Just wonders how many users are willing to modify script to fix such problems?