As part of deploying and testing DHCP infrastructure, utilities like dhcping which can simulate a DHCP handshake are very handy to have. Unfortunately, dhcping is IPv4 (DHCP)-only, with no equivalent tool for IPv6/DHCPv6 in sight. Does anybody know if something like that exists?

I tried using dhclient -6's “no-op” (-n) and “one try” (-1) modes, but they don't seem to work as advertised. Even when specifying -n, dhclient removes existing IPv6 addresses from the network interface I'm using for the test. In addition to this, dhclient always fails in my environment, even though a tcpdump on the same network device shows the DHCPv6 server responding with an advertisement containing the correct (expected) address.

  • While the question is interesting, if tcpdump shows the correct handshake and correct answer, the problem is likely a misconfigured dhclient, and I don't see how an IPv6 dhcping (which would be used to debug the handshake) could help with that. – dirkt May 7 '18 at 6:16
  • To clarify: I am not particularly interested in getting dhclient to work per se. DHCPv6 works for me, I'm just interested in setting up a monitoring plugin (nagios-style) to make sure it remains that way, i.e. that the server is always responding. For IPv4 we have a monitoring plugin that essentially does the equivalent of calling dhcping. It was merely trying to use dhclient -6 (to replace dchping) for DHCPv6 monitoring that failed. – haasn May 7 '18 at 8:46
  • Please edit the question with this additional information; the comments are not guaranteed to stay. – dirkt May 7 '18 at 11:07

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