SLAAC(autoconfig) vs DHCPv6

TJ trejrco at
Mon Aug 18 15:46:13 CDT 2008

>-----Original Message-----
>From: Dale W. Carder [mailto:dwcarder at]
>Sent: Monday, August 18, 2008 4:24 PM
>To: surfer at
>Cc: nanog at
>Subject: Re: SLAAC(autoconfig) vs DHCPv6
>Hey Scott,
>On Aug 18, 2008, at 2:33 PM, Scott Weeks wrote:
>> From: "TJ" <trejrco at>
>> As a general rule, most clients are following the "If we gave them
>> static
>> IPv4 addresses we will give them static IPv6 addresses"
>> (infrastructure, servers, etc).  The whole SLAAC(autoconfig) vs DHCPv6
>> is a separate (albeit
>> related) conversation ...
>> ----------------------------------------------------
>> I'm still an IPv6 wussie and would like to learn more before moving
>> forward, so would anyone care to share info on experiences with this
>> decision?
>Here's some pro's and con's to both
>- widely implemented in host v6 stacks that have shipped
>- widely implemented on v6 routers
>- really, really, really broken: it didn't support handing out
>   any DNS info until RFC 5006, thus SLAAC still requires human
>   intervention on a client to make "teh v6 interwebs" work.  It
>   will probably be a painful wait until 5006 gets more widely
>   implemented on hosts (if ever, for some) & routers.

Or rely on IPv4 to do the DNS part.  I call this "cheating", but do not mean
to include the negative connotations that come with that word :).

>- probably "faster" than dhcpv6 w/ tuning timers.  Could be
>   better for mobile thingys.
>- supports RFC 3041 "security by obscurity" extensions.
>- doesn't ship w/ some OS's

And some vendors have publicly stated that they would never support DHCPv6.
While I may not fully believe them (never is a long time), that is atleast
an indication not to expect it "soon".

>- new (danger code), not all features implemented
>- router support for dhcpv6 relay very limited
>- advanced things like prefix delegation don't really seem to
>   have been ironed out.
>In case you weren't confused enough between the two, they are not mutually
>exclusive.  You can run both SLAAC and DHCPv6 at the same time on the same

Indeed, Stateless DHCPv6 is exactly that.  I should have mentioned that by
now - sorry!

>Links for (2) dhcpv6 implementations:


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