[Bug]: Taking longer to connect when outbound and inbound IPs are different (Floating IPs)

[khantzawhein]

Application

Outline Client

Describe the bug

It is taking a bit longer to connect when connecting IP (the one added to the Outline Client) & outbound IP of the server are different.

After connected, the connection works normally.

For instance, in DigitalOcean, I used the Floating IP (a.a.a.a) of the VPS, however the traffic still go through the original VPS IP (b.b.b.b) address since I didn't configure the VPS to redirect traffic through the new Floating IP.

When I connect the server through a.a.a.a, by manually replacing IP in the key, the Outline Client significantly taking longer to connect than I directly connect through b.b.b.b.

Reproducible on iOS & Mac, haven't tested and confirmed yet on Android, Windows.

Steps to reproduce

1. Setup Outline Server on a Digital Ocean Instance.
2. Create Floating IP for that instance.
3. Create a new key and replace the original VPS IP with new Floating IP.
4. Connect via Outline Client.
5. It takes longer to connect than original IP key.

What did you expect to happen?

Connecting via Floating IP (Secondary IP) should not take longer.

What actually happened?

No response

Outline Version

1.13.0 (475891)

What operation system are you using?

iOS, macOS

Operating System Version

iOS 17 / Mac Sonoma (Beta)

Screenshots and Videos

No response