Redirecting an active port

Redirecting an active port

Environment: Web server that requests pages on a specific port from an
application server.
Problem: If a page request comes into the application server during the
restart of a certain web application running on the application server,
the start up gets corrupted.
Question: Is it possible to include some kind of block on the specific
port (or redirect) in the beginning of the shell script that starts the
web application? This would have to work "on the fly" and of course be
reversed at the end of the shell script so that once the application was
up and running, the requests would flow normally.