Hey everyone, I'm trying to evaluate Appgate SDP for a potential project at work and hit a wall right at the start. I can't get the Linux client to connect from my Ubuntu 24.04 laptop.
I downloaded the `.deb` package (version `5.4.3`) from our system and installed it fine. The GUI app launches, and I can enter the controller URL and my credentials. It seems to authenticate, but then it just hangs on "Connecting..." and eventually times out. There's no helpful error in the GUI, just a generic failure.
I checked the logs in `/opt/appgate/var/log/` and found this repeated error in `client.log`:
```
ERROR [2024-...] [tunnel] Failed to establish tunnel: unable to resolve controller hostname.
```
The weird thing is, I can ping and `nslookup` the controller hostname from the same terminal without any issues. The network seems fine.
Has anyone gotten the Linux client working on a recent Ubuntu distro? I'm wondering if:
- Is there a known issue with 24.04's libc or networking stack?
- Do I need to open specific ports besides the default ones? The docs are a bit vague.
- Are there any `systemd-resolved` or `NetworkManager` conflicts I should check?
I'm comfortable with CLI debugging, so if there's a config file or a way to run the client with more verbose logging, I'd love to try that. Any pointers would be super helpful before I have to tell my team this might not work for our Linux users.
Learning by breaking
That specific DNS resolution error from the client, while nslookup works, is a classic Appgate Linux client issue. It's likely because the client runs in a confined environment that can't use your system's DNS resolver. Your suspicion about `systemd-resolved` is on point.
You'll need to check if the client is being blocked from accessing port 53. More directly, try this workaround: edit `/opt/appgate/config/config.json` (you'll need sudo) and add a `dnsServers` array to the configuration, specifying your DNS servers directly, like this:
```json
"dnsServers": ["8.8.8.8", "1.1.1.1"]
```
Stop and restart the client service (`sudo systemctl restart appgate-sdp`) after making the change. This bypasses the system resolver entirely. It's a known quirk, especially on newer distributions with strict sandboxing.
Data > opinions
You've already found the key clue. That log entry is telling you the client's internal network namespace can't perform DNS lookups, even though your host can. The `dnsServers` config fix mentioned is the standard workaround.
Since you're on Ubuntu 24.04, also check if the client's AppArmor profile is interfering. Run `sudo aa-status` and look for `appgate`. If it's enforcing, you might need to add a local policy allowing network access for DNS, or temporarily set it to complain mode for testing.
If the config file edit doesn't stick after a restart, make sure you're editing the right file - sometimes service updates overwrite it.
benchmark or bust