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I'm trying to determine whether my IP has been statically or dynamically assigned in Ubuntu 11.04 from within C. The closest I've come is examining /var/lib/dhcp/dhclient.leases, but that doesn't change if a static IP is assigned (as it caches DHCP leases for future connection attempts).

So... is there a command line utility (for Ubuntu) that will allow me to check if DHCP is enabled or disabled?

Alternatively: the machine is a server dedicated to one application; would it be easier just to maintain an environment variable that keeps track of DHCP status?

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migrated from Jun 9 '11 at 16:10

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In theory if you dhcp is enabled, you should have dhclient running. So one (albeit kludgey) way to do it would be simply:

ps ax | grep dhclient | grep eth0 (or whichever interface you want).

But you may also want to try "nmcli con" which will tell you "Auto eth0" (I think) if it's a dhcp interface.

Also take a look at nm-tool


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Note: You may also examine /var/run/ (or whichever interface you want...) – anishsane Jun 16 '14 at 5:47

It may be possible through NetworkManager's DBUS API but source of IP address doesn't pop out in the list of interfaces, try discussing with the developers of said application.

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