IPv6 Deployment for the LAN

Thu Oct 22 00:20:04 UTC 2009

> What it does deprive them of, with increasing layers of NAT or proxy
> service, is "dial-in" access.  Many do not require this feature.  The
> cost of providing it is increased support costs; debugging two
> networks and three or four protocols.  Today, even debugging IPv4
> problems with customers is problematic and costly enough.
>   

The WAND Networking Research group did some measurements on the number 
of clients that accepted at least one incoming TCP connection from 
external to their network and presented their results at NZNOG 2009 ( 
http://www.wand.net.nz/~salcock/nznog09/spnat-nznog.pdf ).  The number 
of people that successfully accepted at least one incoming TCP 
connection was somewhere from 30% to 44%.  Most of it seemed to be from 
people using bittorrent, but about half was from other protocols.

I'm not so sure it's entirely obvious that people aren't accepting 
incoming TCP connections.