N-Central - Agents Disconnected

[Slaters Kustum Machines]

I have some computers that are showing disconnected and cannot figure out how to connect them. I have a mix of both connected and disconnected devices in my office, which is where my N-Central server is. Flat network so no VLAN issues.

The laptop I am currently using is showing disconnected. It was working initially. I have no idea what changed. I have checked the applianceconfig and the serverconfig xml files and from what I can tell they match up. I have also tried uninstalling, re-installing the agent with no luck. This is a domain environment with the probe running on the DC and agents on all other devices, but I also have some agents on residential machines with no probes on the network showing the same behaviour.

I have a ticket in with N-Able, but thought I would check to see if anyone here had seen this issue or had something else to try.

I forgot to mention that I can ping the internal and external IP's as well as the URL from the locally affected machines and external/URL from machines outside the office.

 

[Frick]

Ate they fully disconnected, or is just the connectivity service/check failing?

Is your n-central server hosted or on your own hardware? *Ignore this one as I see your server is local in your office.

Was your server recently upgraded?

 

[Slaters Kustum Machines]

I am going to say fully disconnected because all of the checks are failing/stale/no data on my laptop that had worked previously and on the newly configured machines, the dashboard shows the item, but no data. I installed 10.1 and have not done any upgrades. I have only been running n-central for about a month. I did try restarting the n-central server as well, which happens to be a VM.

 

[Frick]

Check if the "Windows Agent" service is running on the disconnected devices.

 

[Slaters Kustum Machines]

Check if the "Windows Agent" service is running on the disconnected devices.

Yep as well as the "Windows Agent Maintenance Service". Those are the only two that stuck out. This laptop had several services before the uninstall/re-install, but they are now gone due to the machine not communicating to the server.

 

[Frick]

Have you messed with or edited any of the settings for the devices in ncentral, or the defaults?

In ncentral, go into the computer and then it's settings, make sure it's set to report to your n-central server

 

[Slaters Kustum Machines]

Have you messed with or edited any of the settings for the devices in ncentral, or the defaults?

In ncentral, go into the computer and then it's settings, make sure it's set to report to your n-central server

Under Local Agent? That shows the correct info under Communication Settings.

 

[Slaters Kustum Machines]

I assume your n-central server has an internet resolvable address. Have you configured your local dns to resolve to your server locally?

Yes, it has an internet resolvable address and in the n-central config I have it set with two addresses. The first is the URL (internet resolving) and the second is the private IP of the server. This may not be the correct way, but it has the option built in and was working.

 

[Frick]

Do you have devices having the same issue that are not local to the ncentral server, or is the issue only happening within your office?

I am wondering if it is a connection/routing issue. Can you connect your laptop to a non-office network, like your home or a phone hotspot to see if it shows as online then?

 

[Slaters Kustum Machines]

It seems to be happening with out of office devices as well, but not all. When I am back in the office tomorrow I will try a different network though.

 

[4ycr]

This is why I left N-Able, agents were going offline all the time. At one point half my agents didn't work. Their support only came up said to reinstall the agent each time and as it was happening to some of the same clients multiple times I ended up leaving them. I had one of their engineers go over my setting, he made a few suggestions that I followed but it still happened.

Hope you get it sorted though, oh and mine was hosted by them.

 

[YeOldeStonecat]

What type of internet connection are you on?
What hardware is between your N-Cent server and the internet?

 

[Slaters Kustum Machines]

This is why I left N-Able, agents were going offline all the time. At one point half my agents didn't work. Their support only came up said to reinstall the agent each time and as it was happening to some of the same clients multiple times I ended up leaving them. I had one of their engineers go over my setting, he made a few suggestions that I followed but it still happened.

Hope you get it sorted though, oh and mine was hosted by them.

I have re-installed the agent on my personal laptop with no change, they want logs so we'll see what they come up with.

 

[Slaters Kustum Machines]

What type of internet connection are you on?
What hardware is between your N-Cent server and the internet?

We have a fiber connection into our office which then goes through a patch panel to our ESXi host, which has our pfSense firewall\router. Our N-Central server is on the same host. Less than half of the resources are being used on the host.

 

[YeOldeStonecat]

Fiber as in biz level symmetrical? Or residential?
I'm curious about port 443 being allowed, and the next thing to check is proper "loopback" functionality on your firewall.

 

[Slaters Kustum Machines]

Fiber as in biz level symmetrical? Or residential?
I'm curious about port 443 being allowed, and the next thing to check is proper "loopback" functionality on your firewall.

It's not symmetrical, but it is the business package from our provider. It's 25/2. How would I go about checking proper loopback functionality? Hmm, I just checked and going to https://ncentral.mydomain.com doesn't work. But standard http does, so it may be an issue with port 443. I'll see what I can come up with.

 

[Slaters Kustum Machines]

canyouseeme.org shows port 443 as open. I have the ports open in pfSense from what I can tell. Interesting. If I set pfSense Src. Port for the https:// rule to https and I try to hit my ncentral url externally I get this error: "Potential DNS Rebind attack detected.
Try accessing the router by IP address instead of by hostname." But if I set the src port to any the connection times out.

 

[Slaters Kustum Machines]

If I disable the rebind check I get the pfSense login page, so I got something screwed up.

 

[Slaters Kustum Machines]

I got 443 to work. Now I will have to see about getting the agents to connect. I'll give them some time.

Edit: Woohoo, my laptop checked in. We'll see about the rest.

 

[YeOldeStonecat]

Looks like we're on the correct path. Gotta have the public face of it resolving properly. And yeah port 443 often already conflicts with something....tis where multiple IPs (a full block) comes into play to help you out.