I have three local domains for my Nginx Proxy Manager running on a VPS, for my self-hosted Nextcloud and my Proxmox-WebGUI both running on my local Homeserver. They follow the scheme service.dataprolet.duckdns.org.
Now I use Uptime-Kuma to monitor my services including the three domains and for some reason those three domains constantly time out after 48 seconds. I already set up the retries to 3, but to no avail.
I also use Pi-hole and Unbound and thought, that might be an issue, but testing my DNS using dig, mtr, traceroute, nslookup and host all returned normal values and no errors.
Does anybody have any idea what could cause this? I’m kind of clueless at this point. Thanks in advance!
EDIT: I don’t get it.
I can’t ping duckdns.org on my home server. I only get 100 % packet loss. I can open the website in my browser though. I also can’t ping www.duckdns.org, which redirects to appservers-duckdns-prod-1630339571.ca-central-1.elb.amazonaws.com. Also gets 100 % packet loss.
I’ve added duckdns.org to my Uptime-Kuma and it got flagged as down because timeout of 48000ms exceeded but my other domains using DuckDNS were unaffected.
I added another local domain to Uptime-Kuma to see the differences of having ignoring SSL errors tuned on or off and the number of retries:
Nextcloud
Ignore SSL error = false
Retries = 2
Proxmox
Ignore SSL error = true
Retries = 1
VPS
Ignore SSL error = false
Retries = 1
Homepage
Ignore SSL error = true
Retries = 2
Throughout the day only the newly added Homepage got flagged as down for 5 times. The 3 others were up the whole time.
seems like your DNS works fine but your certs doesn’t. Are you able to connect to your services on your browser normally, with SSL?
Edit: please also try curl -4 and curl -6 to your services from within the uptime kuma container to see if theres an ipv4/v6 issue
Another edit: seems like there is a dataprolet URL in your post and a datenprolet URL in your comments. It might just be a typo so also check that too.
Yeah, it works fine through my browser. Sometimes the websites load a little longer. I feel like it’s an issue with DuckDNS as it’s seemingly random when it works and when not.
IPv6 doesn’t work:
docker exec -it Uptime-Kuma curl -6 proxmox.datenprolet.duckdns.org
curl: (6) Could not resolve host: proxmox.datenprolet.duckdns.org
Besides that the issue has disappeares since last night. I automatically restart all containers at night and moved from uptime-kuma:1 to uptime-kuma:latest. That shouldn’t make a difference, but maybe it did?
And it’s not a typo in my config, but in my post. But good catch. ;)
Then I guess you only define an A record in the DuckDNS panel. That’s fine.
A while back I ran a somewhat similar Wireguard tunnel and can’t connect. Turns out some MTU settings were lower than the docker’s MTU and that breaks big packets like SSL handshakes. Restarting makes it work fine until things start congesting again.
Suffice to say this would be something I’ll look at if the SSL errors reoccurs
So the MTU of Tailscale is actually 1280, but is the connection even going through the VPN or rather through my VPS, when Uptime-Kuma is trying to connect to my local domain?
Thanks, since I access my home network and server through the public IPv4 of a VPS via Tailscale this could actually be the issue. I’ll look into it, when I find the time.
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seems like your DNS works fine but your certs doesn’t. Are you able to connect to your services on your browser normally, with SSL?
Edit: please also try
curl -4andcurl -6to your services from within the uptime kuma container to see if theres an ipv4/v6 issueAnother edit: seems like there is a
dataproletURL in your post and adatenproletURL in your comments. It might just be a typo so also check that too.Yeah, it works fine through my browser. Sometimes the websites load a little longer. I feel like it’s an issue with DuckDNS as it’s seemingly random when it works and when not.
IPv6 doesn’t work:
Besides that the issue has disappeares since last night. I automatically restart all containers at night and moved from uptime-kuma:1 to uptime-kuma:latest. That shouldn’t make a difference, but maybe it did?
And it’s not a typo in my config, but in my post. But good catch. ;)
Then I guess you only define an A record in the DuckDNS panel. That’s fine.
A while back I ran a somewhat similar Wireguard tunnel and can’t connect. Turns out some MTU settings were lower than the docker’s MTU and that breaks big packets like SSL handshakes. Restarting makes it work fine until things start congesting again.
Suffice to say this would be something I’ll look at if the SSL errors reoccurs
So the MTU of Tailscale is actually 1280, but is the connection even going through the VPN or rather through my VPS, when Uptime-Kuma is trying to connect to my local domain?
It shouldn’t go through the VPN although idk how to verify that. Do you still have the timeout errors in your monitors? What do those errors say?
After changing the MTU to 1200 I have no timeouts anymore, but a lot of
read ECONNRESETerrors. -.-I just changed the Docker’s MTU to 1200 and will observe the change.
Thanks, since I access my home network and server through the public IPv4 of a VPS via Tailscale this could actually be the issue. I’ll look into it, when I find the time.