portreserve 0.0.4-1 (armhf binary) in ubuntu bionic

 The portreserve program aims to help services with well-known ports
 that lie in the bindresvport() range (currently 600-1023).
 It prevents programs requesting a port to the libc from occupying
 a real service's port by occupying it itself, until the real service
 tells it to release the port (generally in its init script).