Why does a NFS or NIS service block the port of another service?

Solution Verified - Updated -


  • CUPS fails to start. It cannot bind to port 631. netstat -tulpen | grep :631 shows an NFS or NIS service is bound to this port.
  • Why would portmap give out as a random port a well-known port 995 (POP3 SSL) to rpc.statd?
  • Why can't portmap assign a random port from unprivileged (> 1024) ports only?


  • Red Hat Enterprise Linux
  • NFS and/or NIS services configured

Subscriber exclusive content

A Red Hat subscription provides unlimited access to our knowledgebase, tools, and much more.

Current Customers and Partners

Log in for full access

Log In

New to Red Hat?

Learn more about Red Hat subscriptions

Using a Red Hat product through a public cloud?

How to access this content