DNS issues

afare · 2023-07-13T19:11:29.000Z

I’m stumped on this one… I have never had this issue before in my 8 years of doing this…

I can’t ping MOST of my hostnames… but i can ping their IP’s… my DNS is showing everything, but still cant ping… but I CAN RDP using the hostname… but can’t ping??

anyone know how to fix this? I’m stuck, nothing changed other than I recently setup a server by request from corp to install Certero on…

anyone have any ideas on this?? thanks.

solidptoyonj · 2023-07-13T20:03:04.000Z

A bit confused by your description. You mean you can’t resolve most of the hostnames on your LAN / DOMAIN?

What do you get when you try nslookup to one of the hostnames? Can you post the output?

Also, what if you try to ping using the FQDN of one ( or more ) of the affected hosts?

netcacique · 2023-07-13T21:53:36.000Z

Have you checked the windows firewall? Is it stopping ICMP?

afare · 2023-07-14T12:00:13.000Z

Sorry, Yes I can no longer ping in my LAN/Domain using hostnames other than maybe 10-20 computers… I have over 200.

Yes, When I nslookup a hostname that wont ping, It does come back correctly, Displays the DC hostname / IP & displays the computer with issues FQDN / IP.

No, pinging with the FQDN doesn’t change anything… I’ve seen & fixed some weird issues, but this one is kicking my butt… I’ve spent hours messing with it. I think I just need a vacation… It’s that time.

foo · 2023-07-16T19:31:09.000Z

Eliminate firewall first, drop it and see if the issue goes away, if so start looking at the firewall, sounds like the culprit.

Also have they possibly switched network profiles from “Domain” to “Public”, happens for a lot of reasons. Annoying as hell though.

solidptoyonj · 2023-07-17T15:32:50.000Z

Hmmm. Vacation does sound in order

Given that your nslookups are working, I’m assuming you can " reach " your affected hosts via FQDN / Hostname without issue? ie: via SMB/RDP anything else?

Just not getting an ICMP reply from ping to hostname while still getting an ICMP response to ping direct to ip for those affected hosts, yes?

Bouncing a bit off of what foo said above, are you experiencing the symptom from multiple machines ( aka not just your personal box that has this ping problem, but various boxes? ). If the problem is consistent regardless of which machine you ping from, then I’d look at firewall and endpoint protection software. If not, strongly suggest what he’s talking about, though it would surprise me that connection profile would mess that up for only certain hosts. No local hosts file in play?

Oh, try disabling IPv6 on the affected machine your’e trying to ping from?

You may also consider testing from a fresh non-domain-joined machine to see if there are firewall GPO’s affecting the outcome.

Barring that? I agree, take a break, relax, and come back with a fresh mind.

Cheers, and good luck!