turning on comcast v6

Sat Jan 4 06:06:56 UTC 2014

On Fri, 03 Jan 2014 20:52:25 -0500, Owen DeLong <owen at delong.com> wrote:
> Not entirely true, actually… If you’re willing to work hard enough at  
> it, most hosts can be “encouraged” to renew early.

Short of commandline access, no there isn't. (crashing or otherwise  
triggering a reboot, isn't a "renew"; that's a full broadcast restart)   
And RENEW isn't at issue as that's a unicast request directly with the  
original DHCP server.  Simply turning up your own instance will do nothing  
there. (attempting to impersonate the real server isn't what were talking  
about.)

For IPv6, you can become a/the router for a segment with the origination  
of a single packet. Instantly.  That's something you can never do with  
DHCPv4.

> Well… Sure, 15 years after DHCP attacks first started being a serious  
> problem… I doubt it will take anywhere near 15 years for RA guard on by  
> default to be the norm in switches, etc.

It'll **NEVER** be a default because it breaks too many clueless people's  
networks.  Just like, surprise, DHCP "guard" isn't on by default in any  
gear I'm aware of.