Pedersen, Sean (Sean.Pedersen) writes:

Does anyone out there have any experience with a script, tool or appliance that would help manage the creation and maintenance of DNS records for Layer 3 interfaces on routers and switches?

Hi Sean, Part of Netdot's (Network Documentation Tool - netdot.uoregon.edu) functionality is to produce automated DNS zone exports based on the IPAM information it manages, including L3 devices and their interfaces.

We'd like to move toward this practice to help with troubleshooting and IPAM, but it's not feasible to do it manually. At a minimum, I was mulling over the idea of writing a script that would poll a device via SNMP to obtain interface information, parse it, compare the results to DNS, then generate a report if it found a miss. It wouldn't be fully-automated, but it would be better than doing that portion of the work manually. Cleaning up dead entries would be another issue.

Writing the scripts isn't too difficult, but as you write, you still need to detect dead entries, differentiate between an interface disappearing because it was deprovisioned, and the sudden disappearance of a large number of IFs due to a script failing (is 1 dead entry acceptable ? 10 ? 1000 ?) Cheers, Phil

On Thu, Oct 18, 2012 at 12:57:16PM -0700, Pedersen, Sean wrote:

Does anyone out there have any experience with a script, tool or appliance that would help manage the creation and maintenance of DNS records for Layer 3 interfaces on routers and switches?

http://cluepon.net/ras/generate_dnsptr_generic_php A relatively simple example using php, with the net-snmp module and Net_IPv4 from PEAR. For extra bonus points, it parses your BGP state and uses any neighbor ASNs it finds for the remote side of your /30 or /31s, and it resolves point-to-point SVIs to physical ports by checking against the vlan tables. The later part was only tested on Cisco 6500s, and I haven't touched that code (or those boxes) in many many years, so no guarantees about using it on anything else. :) Out of date DNS PTRs in traceroute make baby jesus cry, so please use copiously. -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)

On 2012-10-18, at 14:57, "Pedersen, Sean" <Sean.Pedersen@usairways.com> wrote:

Does anyone out there have any experience with a script, tool or appliance that would help manage the creation and maintenance of DNS records for Layer 3 interfaces on routers and switches?

http://www.nanog.org/meetings/nanog26/presentations/stephen.pdf ftp://ftp.isc.org/isc/toolmakers/

We'd like to move toward this practice to help with troubleshooting and IPAM, but it's not feasible to do it manually. At a minimum, I was mulling over the idea of writing a script that would poll a device via SNMP to obtain interface information, parse it, compare the results to DNS, then generate a report if it found a miss. It wouldn't be fully-automated, but it would be better than doing that portion of the work manually. Cleaning up dead entries would be another issue.

AS6461 once had the bulk of its reverse DNS auto-generated from awk scripts. It's the only way to travel. Joe