This will just work on any Unix/Linux systems:
Where are the configuration files?
find / -name "conf"
Where the gateway is defined (or anything else)?
find /etc -exec grep -i "gateway" \; 2>dev/null or grep -ir "geteway" /etc 2>/dev/null
What command should I use to reboot the system?
man -k reboot
Read man pages is very important so take is easy and go trough it you will save time and your system.
Packages tools will give usefull informations about your systems.