DNS and IPv6

Hi, I have a home network with debian (sid) systems and an ISDN router (Elsa Lancom). The router is also DNS and DHCP server. When I use telnet between two debian systems, the router dials to my ISP, because telnet-client and telnet-server sends DNS requests Typ (IPv6 requests) to the router.

nslookup and host always consult a dns server - never local /etc/hosts

: telnet and ping works fine without dns-requests !!! Anybody has an idea to fix this problem ??? best regards Lars Steidinger