Change port for one IP with rinetd?-> Cannot assign requested address.

[ethpi]

Hi,

I'd like to change the port for outgoing traffic to one specific external IP. I use this configurationline:

12.34.56.78 443 12.34.56.78 12345

But rinetd tells me:

rinetd error: couldn't bind to address 12.34.56.78 port 443 (Cannot assign requested address)

If I use

127.0.0.1 443 12.34.56.78 12345

it works perfectly. Does rinetd doesn't work for external IPs?

Background:
I'd like to make my collabora server to speak with my nextcloud server (12.34.56.78) that doesn' listen on 443 but due to security reasons on port 12345. Because my collabora server shall connect to other nextcloud servers on the standard 443, I can't change default outgouing port of collabora server.

[Pentium4User]

rinetd needs to listen on an interface with an IP address. On the left side you need to use an IP address that is assigned to your system.