DNS resolvers (clients) typically make recursive queries, meaning that the server is expected to return an answer to the resolver without the resolver having to make any further queries.
DNS servers typically make non-recursive queries. They will often have to follow a chain of NS records to find a server that has the info they are after, because other servers won't do it for them.
I believe, however, that a DNS resolver is supposed to be able to handle servers that refuse to handle recursive queries. Is this a bug in dnsjava? Or is handling of non-recursive queries supposed to be optional?
Cheers
ADK
Mark Imel wrote:
Thanks for the response. You gave me the clue that i needed to fix the
problem...
You said: 'The whole point of the DNS is for the server to do that work, not
the client. James is just a DNS client.'
And i realized, that in my foolishness, i wasn't using my isp's dns servers,
but some root dns servers that won't do that work. (eg: A.GTLD-SERVERS.NET)
Now that i'm using my isp's dns servers, they are doing the work of
'de-referencing' the authoritative records and obtaining the MX-records that
james needs.
Thanks again,
--mark imel
----- Original Message -----
From: "Noel J. Bergman" <[EMAIL PROTECTED]>
To: "James Users List" <[EMAIL PROTECTED]>
Sent: Friday, February 07, 2003 10:51 AM
Subject: RE: Resolving MXs
correctBTW: I'm using the dns 1.2.3 which is compatible with James2.1.We have replacement dns code that I wanted to get more testing on before
putting it out, so I'll put up a test build for you to try.
I'm wondering about one of your local dns servers not giving you the
results. What software is running the DNS on each of your servers? Wehave
bind 8 running on one gateway, and bind 9 running elsewhere. The wholeresult,
point of the DNS is for the server to do that work, not the client. James
is just a DNS client.
--- Noel
-----Original Message-----
From: Mark Imel [mailto:[EMAIL PROTECTED]]
Sent: Friday, February 07, 2003 12:11
To: James Users List
Subject: Re: Resolving MXs
Thanks for the response Noel,
Its not clear to me that just letting the dns library try again solves the
problem. I'm having this problem with a number of domains and as a
getting a lot of emails bounced back as undeliverable due to this reason.leaning
To me, it seems like either i've really messed up my config, or its a bug
with the DNSServer class. And after stepping through the code, i'm
towards the latter.
IMHO (i'm just a james-newbie, so i'm quite likely to be mistaken), i feel
that if the DNS records come back with no answers, but some authoritative
sources for MX records, those returned authoritative sources should be
queried instead of querying the exact same source.
Regards,
--mark
BTW: I'm using the dns 1.2.3 which is compatible with James2.1.
----- Original Message -----
From: "Noel J. Bergman" <[EMAIL PROTECTED]>
To: "James Users List" <[EMAIL PROTECTED]>
Sent: Friday, February 07, 2003 1:32 AM
Subject: RE: Resolving MXs
Mark,---------------------------------------------------------------------
Are you using the version of dnsjava that came with James, or the newer
version? Those are typically transient. I've seen 25 of them since
mid-August (yes, I grepped the logs). They invariably clear up on the
second attempt.
I ran the same thing, and got this:
$ java -cp dnsjava-1.3.2.jar dig hotmail.com mx
; java dig 0.0
;; ->>HEADER<<- opcode: STATUS, status: NOERROR, id: 25218
;; flags: qr rd ra ; qd: 1 an: 4 au: 4 ad: 14
;; QUESTIONS:
;; hotmail.com., type = MX, class = IN
;; ANSWERS:
hotmail.com. 3248 IN MX 5 mx2.hotmail.com.
hotmail.com. 3248 IN MX 5 mx3.hotmail.com.
hotmail.com. 3248 IN MX 5 mx4.hotmail.com.
hotmail.com. 3248 IN MX 5 mx1.hotmail.com.
;; AUTHORITY RECORDS:
hotmail.com. 63491 IN NS ns1.hotmail.com.
hotmail.com. 63491 IN NS NS2.hotmail.com.
hotmail.com. 63491 IN NS NS3.hotmail.com.
hotmail.com. 63491 IN NS NS4.hotmail.com.
;; ADDITIONAL RECORDS:
mx2.hotmail.com. 3248 IN A 65.54.254.145
mx2.hotmail.com. 3248 IN A 65.54.252.230
mx2.hotmail.com. 3248 IN A 65.54.166.230
mx3.hotmail.com. 3248 IN A 65.54.254.140
mx3.hotmail.com. 3248 IN A 65.54.253.99
mx4.hotmail.com. 3248 IN A 65.54.254.151
mx4.hotmail.com. 3248 IN A 65.54.253.230
mx1.hotmail.com. 3248 IN A 65.54.254.129
mx1.hotmail.com. 3248 IN A 65.54.252.99
mx1.hotmail.com. 3248 IN A 65.54.166.99
ns1.hotmail.com. 63491 IN A 216.200.206.140
NS2.hotmail.com. 63491 IN A 216.200.206.139
NS3.hotmail.com. 63491 IN A 209.185.130.68
NS4.hotmail.com. 63491 IN A 64.4.29.24
;; done (405 bytes)
I was able to reproduce those results with both v1.2.3 and v1.3.2 of
dnsjava, on both Windows XP and linux.
--- Noel
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