dhclient -6 and dhclient-script binding IPv6 addresses with infinite lifetimes

Albrecht, Harald harald.albrecht at siemens.com
Fri Aug 30 10:44:46 UTC 2013


I'm using isc-dhclient-4.2.4 on a Kubuntu 13.04 Linux system. Acquiring IPv6 addresses from an DHCPv6 server works so far, without any problems.

However, I've noticed that while the ISC DHCPv6 client properly receives and records the preferred and valid lifetimes for the IPv6 addresses it leases, these lifetimes do not get propagated to the IPv6 stack itself. Instead, DHCPv6 leased addresses are registered with infinite lifetimes with the IPv6 stack. This breaks IPv6 address selection in some cases.

In particular, when looking at dhclient-script, the case branch for BOUND6|RENEW6|REBIND6 simply does:

ip -6 addr add ${new_ip6_address}/${new_ip6_prefixlen}  dev ${interface} scope global

Thus, dhclient-script does not propagate the associated preferred and valid lifetimes to the IPv6 stack. Is there any way to propagate this information (which the DHCPv6 client has as it wrote it to its lease files) down to the IPv6 stack? So that other applications can actually do a correct address selection according to RFC 3484 & friends?

With best regards,
Harald Albrecht

Siemens AG
Industry Sector
Industry Automation Division
Industrial Automation Systems
Gleiwitzer Str. 555
90475 Nuernberg, Germany

Siemens Aktiengesellschaft: Chairman of the Supervisory Board: Gerhard Cromme; Managing Board: Joe Kaeser, Chairman, President and Chief Executive Officer; Roland Busch, Brigitte Ederer, Klaus Helmrich, Barbara Kux, Hermann Requardt, Siegfried Russwurm, Peter Y. Solmssen, Michael Suess; Registered offices: Berlin and Munich, Germany; Commercial registries: Berlin Charlottenburg, HRB 12300, Munich, HRB 6684; WEEE-Reg.-No. DE 23691322

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