>     yamt> Synopsis: Turning off cksum fails localhost ipv4 udp request (named in my case)
>     yamt> State-Changed-From-To: open->analyzed
>     yamt> State-Changed-By: yamt@netbsd.org
>     yamt> State-Changed-When: Sun, 19 Dec 2004 23:43:29 +0000
>     yamt> State-Changed-Why:
> 
>     yamt> pf needs to know *.do_loopback_checksum.
> 
> Is ipfilter involved, too?

i'm not sure.  at a glance, it isn't, unless IPFILTER_CKSUM is defined.

YAMAMOTO Takashi