Davide Libenzi 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 .
But interestingly enough, querying from here for an MX record for returns.bulk.yahoo.com, starting at the root and working forward, seems to return different records than what you found, even though the query ended up at the same nameserver as the one you queried.... E:\Dig>dig +recursive +trace +fail @h.root-servers.net returns.bulk.yahoo.com -t mx ; <<>> DiG 9.2.2 <<>> +recursive +trace +fail @h.root-servers.net returns.bulk.yahoo.com -t mx ;; global options: printcmd .. 518400 IN NS a.root-servers.net. .. 518400 IN NS b.root-servers.net. .. 518400 IN NS c.root-servers.net. .. 518400 IN NS d.root-servers.net. .. 518400 IN NS e.root-servers.net. .. 518400 IN NS f.root-servers.net. .. 518400 IN NS g.root-servers.net. .. 518400 IN NS h.root-servers.net. .. 518400 IN NS i.root-servers.net. .. 518400 IN NS j.root-servers.net. .. 518400 IN NS k.root-servers.net. .. 518400 IN NS l.root-servers.net. .. 518400 IN NS m.root-servers.net. ;; Received 436 bytes from 128.63.2.53#53(h.root-servers.net) in 160 ms com. 172800 IN NS L.GTLD-SERVERS.NET. com. 172800 IN NS M.GTLD-SERVERS.NET. com. 172800 IN NS A.GTLD-SERVERS.NET. com. 172800 IN NS B.GTLD-SERVERS.NET. com. 172800 IN NS C.GTLD-SERVERS.NET. com. 172800 IN NS D.GTLD-SERVERS.NET. com. 172800 IN NS E.GTLD-SERVERS.NET. com. 172800 IN NS F.GTLD-SERVERS.NET. com. 172800 IN NS G.GTLD-SERVERS.NET. com. 172800 IN NS H.GTLD-SERVERS.NET. com. 172800 IN NS I.GTLD-SERVERS.NET. com. 172800 IN NS J.GTLD-SERVERS.NET. com. 172800 IN NS K.GTLD-SERVERS.NET. ;; Received 512 bytes from 198.41.0.4#53(a.root-servers.net) in 100 ms yahoo.com. 172800 IN NS ns1.yahoo.com. yahoo.com. 172800 IN NS ns2.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. ;; Received 210 bytes from 192.41.162.30#53(L.GTLD-SERVERS.NET) in 160 ms 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 170 ms E:\Dig> - 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]
