FOG Server IP Keeps Changing in DNS!

Shuey

OK, so I gained access to the CLI again. There doesn't appear to be any DNS servers configured for my Ubuntu server to talk to (even though it can get out to the Internet for updates without any problem, because it at least has a gateway configured).

This seems to rule out black3dynamite's theory that my Ubuntu server DNS is configured with my DNS server IP...

Where else should I check for these settings, besides in /etc/network/interfaces ??

scottalanmiller

@Shuey said in FOG Server IP Keeps Changing in DNS!:

OK, so I gained access to the CLI again. There doesn't appear to be any DNS servers configured for my Ubuntu server to talk to (even though it can get out to the Internet for updates without any problem, because it at least has a gateway configured).

This seems to rule out black3dynamite's theory that my Ubuntu server DNS is configured with my DNS server IP...

Where else should I check for these settings, besides in /etc/network/interfaces ??

DNS is shown in the file /etc/resolv.conf

scottalanmiller

If you do an nslookup command, it will show you which DNS server it queried at that time, as well.

Shuey

@scottalanmiller I cat'd my /etc/resolv.conf file and there's nothing in it (except for the default two comment lines).

I went ahead and added a DNS server and search (nothing was configured previously and I was unable to ping anything by name) and nslookups are working now.

I've gone so far down this rabbit hole since yesterday that I'm asking myself out of confusion now: "What again does all this have to do with the fact that our AD DNS was changing?" (especially since I didn't even have DNS configured on the Ubuntu server before this morning)

scottalanmiller

@Shuey said in FOG Server IP Keeps Changing in DNS!:

: "What again does all this have to do with the fact that our AD DNS was changing?" (especially since I didn't even have DNS configured on the Ubuntu server before this morning)

I have no idea how or why we are looking at that other than it just needs to be fixed. The DNS settings on the Ubuntu box are definitely not related to the DNS Server entries.

Shuey

@scottalanmiller Cool, at least it's one extra thing that was caught and fixed : )

scottalanmiller

@Shuey said in FOG Server IP Keeps Changing in DNS!:

@scottalanmiller Cool, at least it's one extra thing that was caught and fixed : )

Yeah, might have led to other problems later.

travisdh1

@Shuey said in FOG Server IP Keeps Changing in DNS!:

@scottalanmiller I cat'd my /etc/resolv.conf file and there's nothing in it (except for the default two comment lines).

I went ahead and added a DNS server and search (nothing was configured previously and I was unable to ping anything by name) and nslookups are working now.

I've gone so far down this rabbit hole since yesterday that I'm asking myself out of confusion now: "What again does all this have to do with the fact that our AD DNS was changing?" (especially since I didn't even have DNS configured on the Ubuntu server before this morning)

Do you know if you're using network-manager or just networking? Sounds like the proper DNS config settings are missing. Why this STILL happens annoys me to no end. Anyway, fixes.

Network Manager

nm-tui

and edit the network connection.

Networking

nano /etc/network/interfaces

Add the following line with your preferred DNS server IP addresses

dns-nameservers 8.8.8.8, 8.8.4.4

That's all off the top of my head, so take it with the intended salt.

Shuey

Well, after all the things I've done since starting this thread, the IP is holding steady as the correct static IP it should be. I'll double-check one more time on Monday morning, but I have a feeling it's good to go now.

Dashrender

Windows DHCP can be setup to register non windows clients with DNS. So if there is an active DHCP lease still in place that might explain why the DHCP IP keeps coming back to DNS.

When you "create" your manual DNS entry are you deleting the old one first? Or just changing the original? If you are changing, that might explain why DHCP is able to change it back
I would not expect a manual DNS creation to be changeable by normal MS automation.

Shuey

@Dashrender Yep, that's how ours is setup, but I've never seen a DHCP lease cause an issue like this :-S. And yep, I completely deleted the DNS entry and verified that the deletion replicated through all servers. That's what had me so confused initially (I kept wondering how the heck it could keep coming back from the dead!).

stacksofplates

Check and see if dhclient is running. We had an issue like this with some Pi's (with the dhcpcd client). Static address was set but dhcpcd was still pulling an address.

Also I didn't see it asked. Is NetworkManager and network both running? That causes issues and it seems distros don't disable one or the other

Shuey

@stacksofplates Yep, sorry, I should've replied back about that previously. network manager is not running; it's not even installed ("nmtui is currently not installed" is the message I got when I tried running it). I also checked to see if a service with the name "dhcp" in the name was running; can't find anything.

stacksofplates

@Shuey said in FOG Server IP Keeps Changing in DNS!:

@stacksofplates Yep, sorry, I should've replied back about that previously. network manager is not running; it's not even installed ("nmtui is currently not installed" is the message I got when I tried running it). I also checked to see if a service with the name "dhcp" in the name was running; can't find anything.

Ok. I figured it was worth acting. I haven't noticed the issue with dhclient itself, just dhcpcd.

Shuey

The IP is finally holding steady! Thanks for the feedback guys!