Re: internal network PTR records, necessary?
On Aug 14 2013, SM wrote: Hi James, At 19:06 13-08-2013, James Chase wrote: I noticed if I do a reverse lookup on an internal IP it seems to reference an iana server. Do we have a misconfiguration to be going out there for an answer? Could it be that this iana server was not responding monday morning? See RFC 6303 and RFC 6305. Also see the BIND documentation on automatic empty zones. In BIND 9.9, empty reverse zones for RFC1918 ranges will be defined by default. In earlier versions, since 9.6-ESV-R6, 9.7.5 or 9.8.1 respectively, the same will happen only if you include the option empty-zones-enable yes; explicitly. -- Chris Thompson Email: c...@cam.ac.uk ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: internal network PTR records, necessary?
Thanks for the help figuring out where to direct my research! I'll check all those sources out. Really appreciate it On Wed, Aug 14, 2013 at 7:00 AM, Chris Thompson c...@cam.ac.uk wrote: On Aug 14 2013, SM wrote: Hi James, At 19:06 13-08-2013, James Chase wrote: I noticed if I do a reverse lookup on an internal IP it seems to reference an iana server. Do we have a misconfiguration to be going out there for an answer? Could it be that this iana server was not responding monday morning? See RFC 6303 and RFC 6305. Also see the BIND documentation on automatic empty zones. In BIND 9.9, empty reverse zones for RFC1918 ranges will be defined by default. In earlier versions, since 9.6-ESV-R6, 9.7.5 or 9.8.1 respectively, the same will happen only if you include the option empty-zones-enable yes; explicitly. -- Chris Thompson Email: c...@cam.ac.uk -- Beware of all enterprises that require new clothes. -- Henry David Thoreau ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
internal network PTR records, necessary?
This isn't a problem with bind, that I'm aware of but I was hoping someone could shed a little DNS expertise on a situation that happened Monday morning. I'll be very brief: We started experiencing problems with connectivity from our application servers to a couple database servers. I narrowed the problem down to remote logins over tcp/ip and then by noticing SSH was also connecting slowly, found that the SSH connection was hanging doing a reverse lookup on the internal ip address. After doing some mysql research I was able to find the option to tell mysql to skip this lookup and it solved our problem My dillema has been trying to figure out why the issue started in the first place. There have been no DNS changes for months, and we have never kept PTR records for our internal IPs at our nameservers. This has always just worked, so why would these lookups start hanging monday morning without any configuration changes? Later in the day the SSH connections were quick again within the internal network. Could it just have been that our DNS server wasn't functioning properly for a period of time? We are monitoring this server with nagios so I would be surprised. Should I be concerned about not having internal PTR records? I have never even considered the necessity of setting this up. I noticed if I do a reverse lookup on an internal IP it seems to reference an iana server. Do we have a misconfiguration to be going out there for an answer? Could it be that this iana server was not responding monday morning? ; DiG 9.3.6-P1-RedHat-9.3.6-20.P1.el5_8.6 -x 192.168.1.50 ;; global options: printcmd ;; Got answer: ;; -HEADER- opcode: QUERY, status: NXDOMAIN, id: 1252 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;50.1.168.192.in-addr.arpa. IN PTR ;; AUTHORITY SECTION: 168.192.in-addr.arpa. 300 IN SOA prisoner.iana.org. hostmaster.root-servers.org. 2002040800 1800 900 604800 604800 ;; Query time: 147 msec ;; SERVER: 192.168.1.180#53(192.168.1.180) ;; WHEN: Tue Aug 13 22:00:25 2013 ;; MSG SIZE rcvd: 120 -- Beware of all enterprises that require new clothes. -- Henry David Thoreau ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: internal network PTR records, necessary?
Hi James, At 19:06 13-08-2013, James Chase wrote: I noticed if I do a reverse lookup on an internal IP it seems to reference an iana server. Do we have a misconfiguration to be going out there for an answer? Could it be that this iana server was not responding monday morning? See RFC 6303 and RFC 6305. Regards, -sm ___ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
