IPv6 over PPP Why?

[B.Bonev]

I really don't what's going on here?  Why is that IPv6 on ppp conection? I
want share dialup conn through the FreeBSD gateway.
Jun 16 13:50:15 router ppp[125]: tun0: IPCP: myaddr 212.39.76.96 hisaddr =
212.39.76.242
Jun 16 13:50:15 router ppp[125]: tun0: LCP: deflink: RecvProtocolRej(5)
state = Opened
Jun 16 13:50:15 router ppp[125]: tun0: LCP: deflink: -- Protocol 0x8057
(Internet Protocol V6 Control Protocol) was rejected!
Jun 16 13:50:15 router ppp[125]: tun0: Phase: deflink: IPV6CP protocol
reject closes IPV6CP !
Jun 16 13:50:18 router ppp[125]: tun0: LCP: deflink: RecvProtocolRej(6)
state = Opened
Jun 16 13:50:18 router ppp[125]: tun0: LCP: deflink: -- Protocol 0x8057
(Internet Protocol V6 Control Protocol) was rejected!
Jun 16 13:50:18 router ppp[125]: tun0: Phase: deflink: IPV6CP protocol
reject closes IPV6CP !