The isc-dhcp-client doesn't recognize infiniband devices as a type supported to use it on a dhcp request.
I think this behavior was reported in ticket #786350 (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=786350) but it doesn't have an answer yet.

As an example, I attach the output of a dhcp request over a ib0 device.

$ dhclient -v ib0
Internet Systems Consortium DHCP Client 4.3.1
Copyright 2004-2014 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Unsupported device type 32 for "ib0"

If you think you have received this message due to a bug rather
than a configuration issue please read the section on submitting
bugs on either our web page at www.isc.org or in the README file
before submitting a bug.  These pages explain the proper
process and the information we find helpful for debugging..

exiting.

Thanks,
Oscar Lozano

Dear submitter,

as the package isc-dhcp has just been removed from the Debian archive
unstable we hereby close the associated bug reports.  We are sorry
that we couldn't deal with your issue properly.

For details on the removal, please see https://bugs.debian.org/1143544

The version of this package that was in Debian prior to this removal
can still be found using https://snapshot.debian.org/.

Please note that the changes have been done on the master archive and
will not propagate to any mirrors until the next dinstall run at the
earliest.

This message was generated automatically; if you believe that there is
a problem with it please contact the archive administrators by mailing
ftpmaster@ftp-master.debian.org.

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Thorsten Alteholz (the ftpmaster behind the curtain)