[rbldnsd] AAAA Queries?

[Amos Jeffries]

----- Original Message ----- 
From: "Steven F Siirila" <sfs at tc.umn.edu>
To: "Small Daemon for DNSBLs" <rbldnsd at corpit.ru>
Sent: Saturday, July 29, 2006 5:54 AM
Subject: Re: [rbldnsd] AAAA Queries?


> On Fri, Jul 28, 2006 at 01:49:05PM -0400, Victor Duchovni wrote:
>> On Fri, Jul 28, 2006 at 12:41:33PM -0500, Steven F Siirila wrote:
>>
>> > We are currently using this snippet to query DNSbls.
>> > We do not yet run IPv6 though, so it shouldn't be an issue anyways.
>> >
>> > #define UC(b)   (((int)b) & 0xff)       /* converts char to int (0-255) 
>> > */
>> >
>> > /*
>> >  * dnsbl - read DNS block list data
>> >  */
>> > struct hostent *
>> > dnsbl(char *domain, in_addr_t ipaddr)
>> > {
>> >     char *cp;                           /* general purpose */
>> >     char hbuf[MAXHOSTNAMELEN];          /* temporary host name buffer 
>> > */
>> >     struct hostent *hp;                 /* host node pointer */
>> >
>> >     cp = (char *)&ipaddr;
>> >     sprintf(hbuf, "%d.%d.%d.%d.%s",
>> >             UC(cp[3]), UC(cp[2]), UC(cp[1]), UC(cp[0]), domain);
>> >     if (debug) {
>> >         errmsg("Querying %s", hbuf);
>> >     }
>> >     if ((hp = gethostbyname(hbuf)) == NULL && h_errno == TRY_AGAIN) {
>> >         errmsg("Temporary error querying %s", domain);
>> >     }
>> >     return(hp);
>> > }
>>
>> This code is wrong, it will make queries for "IP.RBL.<parent_domain>" for
>> each domain on your search list. It will on IPv6 capable systems make
>> "AAAA" queries, ... It is not capable of reading the corresponding TXT
>> record. Rewrite using res_init(3), res_search(3), ...
>
> Granted, it is not ideal.  It should probably be changed.  But until there
> is a real need to, it's not going to happen due to other time commitments.
>
> We don't use TXT records either, we write a custom 550 5.7.1 message with
> a URL containing encrypted data, allowing the sender to initiate a three-
> way handshake process, etc...

Which is in itself not the correct way of doing things. !!

The whole point of the TXT field in RBL is to provide a way for the sender 
to know why their email did not get through.

The biggest problem I have as an I/ESP is the number of other providers who 
re-write the 554 (gmail.com being the most annoying with "554 Delivery 
failed"). Simply locating the fault in the delivery chain is vastly 
complicated, since its usually done over the phone to a non-tech.


>
> Thanks for the tips!  BTW, I'm an old-timer when it comes to C coding 
> (1991).
>
> P.S. I hate HTML-only e-mail with a passion as well.  :)
>
> -- 
>
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> Internet Services E-mail: sfs at umn.edu
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