<html><body><div style="color:#000; background-color:#fff; font-family:Courier New, courier, monaco, monospace, sans-serif;font-size:12pt"><div><span>Barry,</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'Courier New', courier, monaco, monospace, sans-serif; background-color: transparent; font-style: normal;"><span><br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'Courier New', courier, monaco, monospace, sans-serif; background-color: transparent; font-style: normal;"><span>The Ubuntu server is delegating a sub-domain to the LB. The LB is authoritative for the domain and is responding to client requests correctly. I removed the </span><span style="background-color: transparent;">@ IN AAAA ::1 from the db file within the primary domain and the response was sent back to the client from the ubuntu server. Leaving the ipv6 RR in the zone db file caused the servfail. I don't know
why.</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'Courier New', courier, monaco, monospace, sans-serif; background-color: transparent; font-style: normal;"><span style="background-color: transparent;"><br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'Courier New', courier, monaco, monospace, sans-serif; background-color: transparent; font-style: normal;"><span style="background-color: transparent;">Thanks,</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'Courier New', courier, monaco, monospace, sans-serif; background-color: transparent; font-style: normal;"><span style="background-color: transparent;">Ryan</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: 'Courier New', courier, monaco, monospace, sans-serif; background-color: transparent; font-style: normal;"><br></div> <div style="font-family: 'Courier New', courier, monaco, monospace,
sans-serif; font-size: 12pt;"> <div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt;"> <div dir="ltr"> <hr size="1"> <font size="2" face="Arial"> <b><span style="font-weight:bold;">From:</span></b> Barry Margolin <barmar@alum.mit.edu><br> <b><span style="font-weight: bold;">To:</span></b> comp-protocols-dns-bind@isc.org <br> <b><span style="font-weight: bold;">Sent:</span></b> Wednesday, June 26, 2013 10:24 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: servfail response message question<br> </font> </div> <div class="y_msg_container"><br>In article <<a ymailto="mailto:mailman.668.1372206152.20661.bind-users@lists.isc.org" href="mailto:mailman.668.1372206152.20661.bind-users@lists.isc.org">mailman.668.1372206152.20661.bind-users@lists.isc.org</a>>,<br> RYAN CHERVENKA <<a ymailto="mailto:ryan_chervenka@yahoo.com" href="mailto:ryan_chervenka@yahoo.com">ryan_chervenka@yahoo.com</a>>
wrote:<br><br>> I currently have a domain example.com authoritative on my Ubuntu server and <br>> it is delegating gslb.example.com to my load balancer.Ý<br><br>www.example.com is a <br>> CNAME for www.gslb.example.comÝ<br>Gslb.example.com has an NS record pointing to <br>> the LB<br><br>Client sends query for www.example.com to Ubuntu DNS server. The <br>> Ubuntu DNS server sends a query to the load balancer for www.gslb.example.com <br>> and the LB responds to the Ubuntu DNS server with the right A record in the <br>> answer section. However, the Ubuntu server responds to the client with <br>> servfail.Ý<br><br>When I look at the pcap from the Ubuntu server, the LB is <br>> responding to it with the correct IP but the dig response from the Ubuntu <br>> server to the client shows "no servers could be reached" when I dig against <br>> the Ubuntu. I also see the same message in the dns response in the pcap <br>>
(obviously).<br><br>Ryans-MacBook-Pro:~ ryanc$ dig @10.10.1.50 www.example.com <-me <br>> querying the Ubuntu for www.example.com<br><br>; <<>> DiG 9.8.3-P1 <<>> @10.10.1.50 <br>> www.example.com<br>; (1 server found)<br>;; global options: +cmd<br>;; connection <br>> timed out; no servers could be reached<br><br><br>Do you have any ideas as to why this <br>> is happening?<br><br>Ryan Chervenka<br><br>Why is the Ubuntu server sending the query to the LB at all? To emulate <br>how a caching server works, you should be sending queries WITHOUT the RD <br>flag, so the Ubuntu server should return a delegation to the LB, and <br>then the caching server should query the LB.<br><br>Regarding the problem as you state it, is the LB responding <br>authoritatively?<br><br>-- <br>Barry Margolin<br>Arlington, MA<br><br>_______________________________________________<br>Please visit <a
href="https://lists.isc.org/mailman/listinfo/bind-users" target="_blank">https://lists.isc.org/mailman/listinfo/bind-users </a>to unsubscribe from this list<br><br>bind-users mailing list<br><a ymailto="mailto:bind-users@lists.isc.org" href="mailto:bind-users@lists.isc.org">bind-users@lists.isc.org</a><br><a href="https://lists.isc.org/mailman/listinfo/bind-users" target="_blank">https://lists.isc.org/mailman/listinfo/bind-users</a><br><br></div> </div> </div> </div></body></html>