[SOLVED] DNS Lookup Failure on static IP, OK with DHCP assigned IP

[woody4165]

Describe the issue
I'm trying to use you fantastic helper scripts, but from a few days from now I'm getting, on both Proxmox servers I have, the error in subject
It happens when is installing dependencies

✗ DNS Lookup Failure
✓ Updated Container OS

• Installing Dependencies...‼ ERROR 100@84 Unknown failure occurred.

What can I check?
Thanks

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Bug reports will be closed after 12 hours of NO activity.

[tteck]

You have DNS issues.

[woody4165]

I can ping, what else can i check and how?
This is strange because I have installed some others LXCs with your scripts and all was fine until a couple of days ago

[tteck]

Was one of the LXC's you installed a DNS app? (Pi-Hole, AdGaurd, ect...)

This is what the script uses to try and resolve github.com to an IP

RESOLVEDIP=$(nslookup "github.com" | awk -F':' '/^Address: / { matched = 1 } matched { print $2}' | xargs)
if [[ -z "$RESOLVEDIP" ]]; then echo -e "DNS Lookup Failure"; else echo -e "DNS Resolved github.com to $RESOLVEDIP"; fi

You can copy & paste this in the Proxmox Shell to see is it's resolving github.com

example:

root@proxmox:~# RESOLVEDIP=$(nslookup "github.com" | awk -F':' '/^Address: / { matched = 1 } matched { print $2}' | xargs)
if [[ -z "$RESOLVEDIP" ]]; then echo -e "DNS Lookup Failure"; else echo -e "DNS Resolved github.com to $RESOLVEDIP"; fi

DNS Resolved github.com to 140.82.114.4

root@proxmox:~# 

[woody4165]

Yes, it seems to work from the shell

root@domotica:~# RESOLVEDIP=$(nslookup "github.com" | awk -F':' '/^Address: / { matched = 1 } matched { print $2}' | xargs)
if [[ -z "$RESOLVEDIP" ]]; then echo -e "DNS Lookup Failure"; else echo -e "DNS Resolved github.com to $RESOLVEDIP"; fi
DNS Resolved github.com to 140.82.121.4

[tteck]

Ok, then the IP issued from the DHCP server to the LXC has DNS issues. https://itsnotdns.itwasdns.net/

[woody4165]

it seems that if I choose dhcp during installation all is ok.
I have tried this:

• create a docker LXC with DHCP, address assigned .67
• delete this LXC purging and destroying during Remove
• create another docker LXC with static .67/24 address and in this case I get the dsn lookup error

[tteck]

Internet check is ok?

[woody4165]

yes

Creating a Docker LXC using the above advanced settings
 ✓ Using local for Template Storage.
 ✓ Using local-lvm for Container Storage.
 ✓ Updated LXC Template List
 ✓ LXC Container 111 was successfully created.
 ✓ Started LXC Container
 ✓ Set up Container OS
 ✓ Network Connected: 192.168.1.67 
 ✓ Internet Connected
 ✗ DNS Lookup Failure
 ✓ Updated Container OS
 - Installing Dependencies...‼ ERROR 100@84 Unknown failure occurred.

[tteck]

Anyway, beings this is a network issue on your end, I'm moving it to discussions.

edit: also change title

[tteck]

I'm not a network guy, but one would think that a DHCP assigned IP or a static IP on the same router should end with the same results 🤷🏻‍♂️

[woody4165]

I'm not a network guy either, but since the dns lookup script you sent me is working outside the main script, why is it a problem from my end?
and how can I solve, since normally I prefer to give a static ip?

a workaround that will surely work is to create it with dhcp and then change it manually from the LXC definition

[tteck]

Because it works with DHCP. Assigning a static IP with the script works. For some reason DNS isn't working for you with a static assigned IP. Not the scripts fault. Works fine in my network.

[tteck]

A static assigned IP with the Docker LXC in my network

    ____             __            
   / __ \____  _____/ /_v4__  _____
  / / / / __ \/ ___/ //_/ _ \/ ___/
 / /_/ / /_/ / /__/ ,< /  __/ /    
/_____/\____/\___/_/|_|\___/_/     

Using Advanced Settings
Using Container Type: 1
Using Root Password: Automatic Login
Using Container ID: 111
Using Hostname: docker
Using Disk Size: 4
Allocated Cores: 2
Allocated RAM: 2048
Using Bridge: vmbr0
Using IP Address: 192.168.86.252/24
Using Gateway IP Address: 192.168.86.1
Using MAC Address: Default
Using Vlan: Default
Creating a Docker LXC using the above advanced settings
 ✓ Using local for Template Storage.
 ✓ Using local-lvm for Container Storage.
 ✓ Updated LXC Template List
 ✓ LXC Container 111 was successfully created.
 ✓ Started LXC Container
 ✓ Set up Container OS
 ✓ Network Connected: 192.168.86.252 
 ✓ Internet Connected
 ✓ DNS Resolved github.com to 140.82.114.3
 ✓ Updated Container OS
 ✓ Installed Dependencies
 ✓ Installed Docker v20.10.21
Would you like to add Portainer? <y/N> 
Would you like to add Docker Compose? <y/N> 
 ✓ Customized Container
 ✓ Cleaned
 ✓ Completed Successfully!

[woody4165]

strangely, really strangely, I found that I have this is Proxmox DNS

search domain: tail6a356.ts.net
DSN address1: 100.100.100.100

but I'm sure I've never done this change

ok for DNS addresses, I know what to write, but what should I put in Search domain?

Again, really strange, and really strange that I have in both Proxmox servers

[tteck]

[woody4165]

ok, all is working now.
Again, I'm sure I've never changed those parameters and I'm pretty scared about it!!!

Thanks, now I will close the thread, solved by my mistake

[woody4165]

Ops, I understood that Tailscale is the one that changed that parameters.
Because I've installed directly on PVE and probably is not good idea

[tteck]

Never a good idea to install anything on Proxmox directly.

[JonTheNiceGuy]

If you're using Tailscale directly on the proxmox device, run this command:
tailscale set --accept-dns=false

This will remove the "magic DNS".