I assume that you have some program that you want to run which uses this port.
It would appear that this port number is associated with a military communications protocol. If we check /etc/services we see
nimserver# grep 1581 /etc/services
mil-2045-47001 1581/tcp # MIL-2045-47001
mil-2045-47001 1581/udp # MIL-2045-47001
It is not disabled because it is not commented out (# mark). However, if we check to see anything is attached to it
nimserver# netstat -an|grep 1581
nimserver#
there is no program using this port on my system. If the state of the port is LISTEN or ESTABLISHED, a program is attached to the port and you will need to find out what this is. You can use the lsof command to discover this. This command is downloadable from
http://www-03.ibm.com/systems/power/software/aix/linux/toolbox/alpha.html
