Milter-greylist

Hi!

I've been experimenting with SPF policy check to drive away spf-aware 
spammers who register bogus 2-nd/3-rd level domains and activate +all 
SPF policy on them. The idea is simple:

- Check incoming IP address against domain SPF policy. Fail if this IP 
is not permitted.
- \ufffdheck some bogus IP-address against the same domain SPF policy. Fail 
if this IP is permitted.

I was a bit puzziled with milter-greylist configuration engine, so I 
hard-coded that bogus IP-address into spf.c.

After about a month with a modified spf check it seems that nothing is 
broken, and I have no more spam from domains with too permissive SPF policy.

Do you consider to implement something like that (with a configurable 
IP-address) into mainline ?

My modifications to spf.c follows:

===CUT==
int spf_check(ad, as, ap, priv)
         acl_data_t *ad;
         acl_stage_t as;
         struct acl_param *ap;
         struct mlfi_priv *priv;
{
         int result=spf_check_intl(ad,as,ap,priv);
         if(result==0) return(result);

         struct mlfi_priv priv_copy,*priv2;
         memcpy(&priv_copy,priv,sizeof(priv_copy));
         priv2=&priv_copy;
         struct sockaddr *sa = SA(&priv2->priv_addr);
         inet_aton("88.14.22.16",SADDR4(sa));
         if(spf_check_intl(ad,as,ap,priv2))
             {
             // Bogus SPF record
             mg_log(LOG_WARNING, "%s: bogus SPF record: lists 
88.14.22.16",priv->priv_queueid);
             return(0);
             }
         return result;
}
#define spf_check spf_check_intl