Does anyone know where I should look to fix this please?

[itojun@iijlab.net]

>It doesn't appear to be actually causing any problems - I don't think
>anyway?
>Apr 25 15:27:57 nanguo sendmail[94293]:
>gethostbyaddr(IPv6:2002:cb01:6005:1::1) failed: 1
>However- its a bit of a nuisance.
>FreeBSD-4.5.

	declare reverse mapping in your DNS database, or have it in /etc/hosts.

itojun