Troubleshooting Help Requested

DustinB3403

@scottalanmiller said in Troubleshooting Help Requested:

So if you traceroute to 8.8.8.8, what do you get?

On the non-working machine, I can't install it.

On the working machine I encounter no issues.

DustinB3403

Maybe it's something with yum-cron as that is installed on this VM, and is set to apply updates. Whereas the other VM has yum cron, but isn't set to apply the updates.

Still doesn't really explain why ping wouldn't work to the internet.

IRJ

What does this look like on the non-working CentOS?

/etc/sysconfig/network-scripts/ifcfg-eth0

is onboot enabled?

Edit: nvm. I see you can ping locally and to the gateway

DustinB3403

@IRJ said in Troubleshooting Help Requested:

is onboot enabled?

Yes.

DustinB3403

This is what I get from the non-working VM.

yum update
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.atlanticmetro.net
 * extras: bay.uchicago.edu
 * updates: centos.s.uw.edu
http://repos-va.psychz.net/centos/7.6.1810/os/x86_64/repodata/repomd.xml: [Errno                                                                                                                                                              14] curl#6 - "Could not resolve host: repos-va.psychz.net; Unknown error"
Trying other mirror.

It just keeps going through all of the mirrors, obviously.

I've disabled and turned off yum-cron and have reboot numerous times. So that isn't it. I can ping locally by IP and DNS from the non-working machine.

DustinB3403

I guess I'll just restore the VM and see what happens from it.

travisdh1

@DustinB3403 said in Troubleshooting Help Requested:

This is what I get from the non-working VM.

yum update
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile

base: mirror.atlanticmetro.net

extras: bay.uchicago.edu

updates: centos.s.uw.edu
http://repos-va.psychz.net/centos/7.6.1810/os/x86_64/repodata/repomd.xml: [Errno 14] curl#6 - "Could not resolve host: repos-va.psychz.net; Unknown error"
Trying other mirror.

It just keeps going through all of the mirrors, obviously.

I've disabled and turned off yum-cron and have reboot numerous times. So that isn't it. I can ping locally by IP and DNS from the non-working machine.

Did I see right that traceroute isn't installed?

DustinB3403

@travisdh1 yes.

DustinB3403

And it isn't required either, as this system has updated fine for months.

travisdh1

@DustinB3403 said in Troubleshooting Help Requested:

@travisdh1 yes.

Makes it difficult to see weather there are peering-point issues between you and the mirror sites.

edit: Yes, I've seen networks block distribution mirror sites before. So much fun trying to get those fixed.

DustinB3403

@travisdh1 said in Troubleshooting Help Requested:

edit: Yes, I've seen networks block distribution mirror sites before. So much fun trying to get those fixed.

But on the very same network, just a different host nothing is blocked. I could of course look at the firewall to see if something was changed. But if changes were to be made, I think I would've been made aware.

And every mirror is blocked. It's as though this device itself is blocked.

black3dynamite

Try ping -4 google.com
It’s probably using ipv6 instead of ipv4

DustinB3403

@black3dynamite said in Troubleshooting Help Requested:

Try ping -4 google.com
It’s probably using ipv6 instead of ipv4

Will test that in a moment. The restore is going.

DustinB3403

@black3dynamite said in Troubleshooting Help Requested:

Try ping -4 google.com
It’s probably using ipv6 instead of ipv4

No change.

And the backup from yesterday has no change either. Grr. . . I don't want to rebuild this VM. . . going further back.

It isn't mission critical either, just irritating.

Obsolesce

Are you using NetworkManager? If so, turn that shit off.

Obsolesce

Try adding 127.0.0.1 to /etc/resolv.conf

DustinB3403

@Obsolesce said in Troubleshooting Help Requested:

Are you using NetworkManager? If so, turn that shit off.

Not using NM.

DustinB3403

@Obsolesce said in Troubleshooting Help Requested:

Try adding 127.0.0.1 to /etc/resolv.conf

No change with adding the loopback.

manxam

@DustinB3403 : The fact that you can ping the gateway/router by name and IP makes me suspect it's the firewall.
AFAIK, there is nothing on a linux box that would allow it to distinguish between LAN and WAN when performing lookups.

scottalanmiller

@manxam said in Troubleshooting Help Requested:

@DustinB3403 : The fact that you can ping the gateway/router by name and IP makes me suspect it's the firewall.
AFAIK, there is nothing on a linux box that would allow it to distinguish between LAN and WAN when performing lookups.

the firewall, OR the default gateway is messed up. Check the routes on the VM.

Unsolved Troubleshooting Help Requested