Holy.. whatever... When issuing a query for an A record, it indeed ONLY returns the SOA record, which is invalid (it should return the NS record..) When issuing a query for a MX recors, it returns some MX records AND the NS records (no SOA, but we didnt ask for that one): returns.bulk.yahoo.com. 1800 IN MX 1 c5.bullet.mud.yahoo.com. returns.bulk.yahoo.com. 1800 IN MX 1 c6.bullet.mud.yahoo.com. returns.bulk.yahoo.com. 1800 IN MX 1 c1.bullet.mud.yahoo.com. returns.bulk.yahoo.com. 1800 IN MX 1 c2.bullet.mud.yahoo.com. returns.bulk.yahoo.com. 1800 IN MX 1 c3.bullet.mud.yahoo.com. returns.bulk.yahoo.com. 1800 IN MX 1 c4.bullet.mud.yahoo.com. yahoo.com. 172800 IN NS ns2.yahoo.com. yahoo.com. 172800 IN NS ns1.yahoo.com. yahoo.com. 172800 IN NS ns3.yahoo.com. yahoo.com. 172800 IN NS ns4.yahoo.com. yahoo.com. 172800 IN NS ns5.yahoo.com. yahoo.com. 172800 IN NS ns8.yahoo.com. yahoo.com. 172800 IN NS ns9.yahoo.com. ;; Received 499 bytes from 66.218.71.63#53(ns1.yahoo.com) in 173 ms
Your resolver should (recursively) try nameservers until it has its answer, so if it gets the answer to the MX query from the yahoo.com nameserver, it should use that one and forget about any lower levels, like dig does. This also helps when using a (decent) recursor. You could even use the same routine for the smartdnshost! :p By the way, I just found out that my Speedtouch router/modem/NAT/dns/whatever can ONLY return A records, NO NS or MX records :'( ----- Original Message ----- From: "Davide Libenzi" <davidel@xmailserver.org> To: <xmail@xmailserver.org> Sent: Sunday, April 08, 2007 11:43 PM Subject: [xmail] Re: ENODNS Error > On Sun, 8 Apr 2007, Davide Libenzi wrote: > >> On Sun, 8 Apr 2007, Ivo Smits wrote: >> >> > It SHOULD check at the nameservers for yahoo.com, if they return the >> > requested record (MX), the resolver has its answer (which is the >> > case!), if >> > it does not return the requested record type, it should retry at the >> > returned NS records. >> >> It does. It tries to go the deeper as possible in the NS hierarchy, then >> issues the query. I'll try to debug, even if the fact that dnsreport >> reports "broken DNS" should be an hint. > > That seems really screwed: > > - A query for returns.bulk.yahoo.com. NS returns an SOA record pointing to > @ns1.yahoo.com. > > - A query for returns.bulk.yahoo.com. NS at @ns1.yahoo.com. returns > returns.bulk.yahoo.com. being a CNAME for mailer1.bulk.scd.yahoo.com. > > - A query for mailer1.bulk.scd.yahoo.com. NS at @ns1.yahoo.com. returns > mailer1.bulk.scd.yahoo.com. being a CNAME for t1.bullet.scd.yahoo.com. > > - A query for t1.bullet.scd.yahoo.com. MX return a broken record > > [EMAIL PROTECTED]:~$ dig t1.bullet.scd.yahoo.com. mx > > ; <<>> DiG 9.3.4 <<>> t1.bullet.scd.yahoo.com. mx > ;; global options: printcmd > ;; Got answer: > ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 28320 > ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 7, ADDITIONAL: 7 > > ;; QUESTION SECTION: > ;t1.bullet.scd.yahoo.com. IN MX > > ;; ANSWER SECTION: > t1.bullet.scd.yahoo.com. 1800 IN MX 0 . > > > > > > > - Davide > > > - > To unsubscribe from this list: send the line "unsubscribe xmail" in > the body of a message to [EMAIL PROTECTED] > For general help: send the line "help" in the body of a message to > [EMAIL PROTECTED] > - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED]