After update Pi-hole gone and Ubuntu damaged

[Gerard]

Today an update was available and updated.
Should not have done that, after years of using Pi-hole, it has been removed.
Pi-hole did not function anymore and Ubuntu was not able to update any more.
Reinstalling was not possible there the update had damaged Ubuntu in such a way, there was no internet connection any more.
I am running a Zimaboard with Ubuntu 20.1
Luckily domoticz and deConz are still alive.
The end of a long time using Pi-hole. I think almost of the start of the project.

[nero355]

I am guessing you only lost 127.0.0.1 connectivity via /etc/resolv.conf so if you edit that to 1.1.1.1 or 9.9.9.9 or 8.8.8.8 you will be able to APT again

And then you can try fixing Pi-Hole v6 too

[Gerard]

I think you do not understanding the issue.
Pi-hole has damaged Ubuntu, I can not re-install Pi-hole.
It has broken Ubuntu, that is really special, how it has done it.
I do not even want to know.
The server has more programs to run, not only Pi-hole.
First action is to repair Ubuntu, than we can have a look to find Ad blocking software which works.
Until now, Pi-hole was a good piece of software. But not anymore.
It is now past history.

[nero355]

@Gerard

I think you do not understanding the issue.

I think you do not understand my reply

But let's start here :

Pi-hole has damaged Ubuntu,

How do you know that your Ubuntu has been damaged ?!
What is not working anymore exactly ?

You wrote :

@Gerard

Luckily domoticz and deConz are still alive.

So you have network connectivity or not ?!

Can you :

• ping 8.8.8.8
• ping ubuntu.com
• Succesfully run 'apt update' for example ?!

[Gerard]

I can run apt update or other commands.
However, nothing will happen, failure connecting with the world.
That is the reason I can not reinstall Pi-hole.
The connection with the outside world is gone.
Tomorrow I will update Pi-hole at the backup server and see what happens.
But first i have to take care, that my homeserver works as it should.

[Gerard]

I have been able to get things running again.
Cleaning and rebooting the server solved the issues.
After reinstalling Pi-hole, no web interface.
I found out that lighttpd was still running. Stopped lighttpd and disabled it)
Now I was able the access the web interface.
However, I have a larger conflict, Pi-Hole is conflicting with deConz.
deConz was using that web address and now Pi-Hole is doing the same.
In the past, Pi-hole was running on 8093 and no 8080.
I have stopped Pi-hole again, there deConz is more important.
Now I have to figure out to change the Pi-Hole Web interface adddress. (New Address)

[mr_mpf]

I thing I got the same issue. After updating with pihole -up the webinterface shows "403 forbidden" and the DNS resolution doesn't work anymore. Can anybody give some hints to analyze or fix.

[oint]

Issue & Setup

So, i noticed that there are a lot of posts more-or-less about this issue, but this is the one that came up for me in a web search, so this is the one i'm going to reply to; my apologies if there is a more appropriate place.

I hope to outline a [temporary?] solution here.

I have encountered a similar issue. After running
$ pihole-up
about an hour ago, unbound DNS resolution broke for me, as did the pi-hole web interface. Details about my setup:

My pi-hole is set up to do its own DNS resolution via unbound, as outlined at:
https://docs.pi-hole.net/guides/dns/unbound/

I typically do all maintenance via ssh, so, to be fair, it's possible that the web interface has been broken for a while without my noticing. In any case.

It looks like maybe some config files got totally clobbered in the upgrade process? My solution:

[Temporary?] Solution

First, i logged into my router and changed DNS resolution back to allowing my ISP to do it, as a temporary measure; i'm not sure whether this is necessary, but it made getting online /at all/ much more convenient.

At this point, DNS resolution on the pi-hole itself seemed to come back, as the commands
$ dig fail01.dnssec.works @127.0.0.1 -p 5335
and
$ dig dnssec.works @127.0.0.1 -p 5335
began returning the expected results, although it's possible that some reboots of the pi-hole that ended up being necessary were the cause of this, i'm not certain.

Second, i took the advice here and killed lighttpd, via
$ sudo service lighttpd stop

I have not yet disabled lighttpd entirely [edit: i have done now, as this appears to be a normal part of the v6 update process; see the "Edit: Additional Info" section below]; i will mess around with whether this is necessary in the coming days, but for now i just wanted to get things working again over the weekend.

Once lighttpd was killed, i was able to access the web interface again. /However,/ i had to reset my login password on the pi-hole, over ssh, via:
$ sudo pihole setpassword
before i was able to actually log in. It seems the update clobbered the password.

Next, after logging in, i visited the DNS settings under System > Settings > DNS. Here, my custom DNS setting was gone, so it seems the update clobbered this, too. I re-added the
127.0.0.1#5335
entry to the "Custom DNS Servers" box at the bottom of the page (note that the interface seems to have changed here; i no longer see four boxes for custom DNS settings in the web interface; only one large box at the bottom of the page).

Once set, i logged back into the router and changed my DNS settings back to allow the pi-hole to do all DNS resolution. Things now seem to be working again.

Conclusion & Questions

I hope this helps others who may run across this issue. Follow-up comments from more knowledgeable users would be most welcome, as, while things are /working/ again, it feels a hack—for example, why do i need to kill lighttpd [edit: this is part of the update process to v6 for most users; see below]? Is this clobbering a one-time thing, or is there a deeper problem? Etc.

Thanks!

Edit: Additional Info

So, part of the issue is that i was unaware that this was a major update;
$ pihole -up
doesn't provide much warning. Others may wish to see the release notes here:
https://discourse.pi-hole.net/t/introducing-pi-hole-v6/75863

In particular:

@PromoFaux

During the upgrade operation, you will be presented with a dialog box asking if you wish to disable lighttpd. Doing so is probably appropriate for most users – unless you are using it to host web pages other than Pi-hole’s, in which case you may choose to keep it enabled. With lighttpd disabled, pihole-FTL will attempt to bind to ports 80 for HTTP and 443 for HTTPS. If there is any conflict on these ports, then it will revert to port 8080 for HTTP.

Since i update over ssh, i, of course, never saw this dialog box. I suspect many others will have missed this note, too. To disable lighttpd permanently:
$ sudo systemctl lighttpd disable
I hope this additional context is helpful.

[nero355]

Then I guess I was right and this still applies : After update Pi-hole gone and Ubuntu damaged - #2 by nero355

I also made some instructions for a similar situation (No DNS Resolving on the Server running Pi-Hole) here : 404 and no DNS after recent update - #9 by nero355

[nero355]

You can change the ports used by Pi-Hole in /etc/pihole/pihole.toml and then restart Pi-Hole via systemctl restart pihole-FTL

[Gerard]

For the moment I have installed Adguard. It works but has never been as good as Pi-hole. It is said that this is the outcome of this update. A simple update which almost destroyed my home server. Maybe I come back overtime, when thing are sorted out. For the moment I am not spending time on this so called update.