[SOLVED] Which cache to flush after changing ip address of other machine?

nix.noob · 03-04-2017, 08:51 AM

I have reconfigured my router so that a "machine A" on my network has a different IP address to the one it previously had.

From another machine ("B", which is running linux mint), I'm trying to ping A by name (rather than by IP) but it's looking for the old IP address, so ping fails.
Pinging the new IP address does work from machine B.

Which cache do I need to flush or which entry should I remove from B to disassociate the "A" name from the old IP?

smallpond · 03-04-2017, 10:19 AM

Host information most commonly comes from a file, NIS, or DNS. Which source are you using and have you updated it? If using DNS and the server has already been updated then restart the local daemon. This could be named, Dnsmasq, or nscd.

nix.noob · 03-04-2017, 01:12 PM

I'm not doing anything bespoke and i'm not familiar with NIS. I presumed I was using DNS but with a layer of caching.
I had already tried searching for how to flush a dns cache before posting but the instructions I found suggest restarting various services (including nscd, dnsmasq, named) or using rndc. But I don't seem to have any of these services.
I do have a dnsmasq process which I've stopped and restarted but that didnt fix my problem.

sundialsvcs · 03-04-2017, 01:42 PM

Routers, and even your own local machine, might have domain-name resolution caches. (Apple's mDNSResponder daemon will also cache "domain not found" results.)

You might also have a /etc/hosts file.

Use the command dig hostname to ask to resolve the name, and you will be told which DNS source provided the answer.

The commands used in MS-Windows are different, but the principles are exactly the same.

nix.noob · 03-04-2017, 02:26 PM

That was it. There was an entry in /etc/hosts, which I've now removed.
Thanks alot