DHCP Client Debug Verbosity

Russell Dekema dekemar at umich.edu
Tue Nov 24 00:27:45 UTC 2015

Good evening,

Beyond issuing the -v flag on the dhclient command line, is there a
way to increase the level or verbosity of debugging output?

I am trying to troubleshoot a problem in which the ISC DHCP client
sends a DHCPDISCOVER and I can see what seems like a valid DHCPOFFER
come back to the client over the wire, but the DHCP client appears to
be ignoring the offer. Adding the -v flag to the dhclient command line
does not produce any useful troubleshooting information; it simply
shows repeated DHCPDISCOVER frames being sent, and nothing else.

I have read the dhclient man page and searched the web extensively but
haven't found any way to do this. I am hoping for a middle ground
between "-v" and running the client in gdb or extensively
instrumenting the code with printf()s (or the like), as those are both
a bit outside my normal realm of expertise.

Thanks in advance for any suggestions.

Rusty Dekema

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