net.cfg is changed by os

I found sometimes when i reboot the system(turn off the power and turn on),the setting of network(/etc/net.cfg) is changed by os automatically,who knows the reason?

may a dhcp issue?

what does dhcp mean?Could you explain to me the details?thank you

The ‘d’ is for dynamic. Every node on the internet needs a unique IP address but users typically don’t need to have the same IP every time. An ISP can dynamically allocate the IP addresses that it owns to the users that are active. A user may get a different IP every time they sign on. DHCP is the protocol where a user who starts off with no IP address, requests one from a DHCP server and is given one. DHCP will also inform the node what its gateway and name server IP’s are. DHCP isn’t limited to the internet. Intranets can use it, and most personal routers, wireless or otherwise, provide DHCP to the end computer node.

The downside to DHCP is that your IP address can be different every time you turn on the computer. It can even change while you are connected.

:smiley: :smiley: :smiley:

but I didn’t use DHCP,I use manual mode to set the ip addr

Maybe dhcp.client is running when it should not. Something uncontrolled in your start-up configuration, maybe?

That sounds very strange. I tend to doubt that the OS is doing this. Is it possible something else is. How about trying this:

$ cd /etc
$ cp net.cfg old_net.cfg

Then in your rc.local file put in the following

date >>/tmp/net.log
diff /etc/net.cfg /etc/old_net.cfg >>/tmp/net.log

That way you can at least keep track