I don't think you can do that. Is your ISP blocking traffic or are you just doing this to see if you can? I just can't think of a use case for what you're trying to do and wondering if there could be a different way to achieve what you're trying to do.
On Fri, Apr 18, 2025, 12:16 PM TSS <t...@mg-1.uk> wrote: > Hi again. I hope it's not unwelcome to ask a pf question here; I hope > this one isn't too elementary. > > I have a daemon that sends and receives UDP packets on port 1337. For > reasons, I would like to use pf on my computer (i.e. the one that's > running the daemon) to take the daemon's outbound UDP packets, which it's > emitting from port 1337, and actually send them out to the internet as > if they're coming from port 31337. Also, I'd like UDP packets coming in > to port 31337 to be received by the daemon, which is listening for them > on port 1337. In ASCII art, that's: > > . . | > +-------+ o * . ~ * | > | my |--> UDP 1337 --> % . pf : . --|--> UDP 31337 --> clouds > |special| + . magic + | and > |daemon |<-- UDP 1337 <-- * _ , + <--|--- UDP 31337 <-- stuff > +-------+ + * o . ~ | > | > INSIDE MY OPENBSD MACHINE | OUT ON THE INTERNET > | > > All IP addresses involved should remain the same throughout, and in that > way this feels a little bit different to NAT: there's no address > translation since the addresses do not change. Does anyone know if it's > possible to get pf to do this? > > Search engines have not helped me out with this one, but my search skills > were dubious even before the AI era. > > If not pf, maybe relayd would work? I worry that its extra layer of > indirection might be slow, and I'd like this process to be as fast as it > can be. > > Thanks for any tips! > --T > >
