I set a new slave to launch via jnlp. The links it suggests are on port 8080
(the default) where as I have set hudson to run on port 80 i.e.

hudson suggests:
"Run from slave command line:

javaws http://172.16.158.136:8080/computer/172.16.159.154/slave-agent.jnlp

Or if the slave is headless:

java -jar slave.jar -jnlpUrl
http://172.16.158.136:8080/computer/172.16.159.154/slave-agent.jnlp"
and using that fails immediately

what it should be the same but with :80

It a small annoyance that (I assume) the user would figure pretty quickly, but
it'd nice to have fixed.