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Description of problem:
ss does not output listening udp ports

Version-Release number of selected component (if applicable):
2.6.32-17.el6.x86_64

How reproducible:
always

Steps to Reproduce:
1. ss -ul
  
Actual results:
column headings only

Expected results:
output of all listening udp sockets

Additional info:
netstat -ul works properly

This sounds like bug #691100 to me.

Josh, could you confirm?

I can confirm that it is the same behavior as that bug, yes.

Thank you.

    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Cause
    Invoking 'ss -ul' didn't list open UDP sockets.
Consequence
    EL ss users couldn't list open UDP sockets.
Fix
    The ss utility was patched to list UDP sockets.
Result
    The ss utility now correctly reports open UDP sockets.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2013-0417.html