Bug 1388413

Summary: rpcbind uses an undocumented UDP port
Product: Red Hat Enterprise Linux 7 Reporter: divya.n.gopi
Component: rpcbindAssignee: Steve Dickson <steved>
Status: CLOSED NOTABUG QA Contact: Yongcheng Yang <yoyang>
Severity: high Docs Contact:
Priority: unspecified    
Version: 7.0CC: eguan, yoyang
Target Milestone: rc   
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Hardware: All   
OS: Linux   
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Last Closed: 2017-04-08 15:47:29 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description divya.n.gopi 2016-10-25 09:53:49 UTC 
Description of problem:
rpcbind not only listens to the tcp port 111 and UDP port 111, but to an undocumented UDP port.

Steps to Reproduce:
Details of the netstat command run on my test machine shows the below output. Here 'rpcbind' has opened the port 993:

netstat -anp |grep rpc
tcp        0      0 0.0.0.0:111                 0.0.0.0:
*                   LISTEN      4634/rpcbind
tcp        0      0 :::111                      :::
*                        LISTEN      4634/rpcbind
udp        0      0 0.0.0.0:993                 0.0.0.0:
*                               4634/rpcbind
udp        0      0 0.0.0.0:111                 0.0.0.0:
*                               4634/rpcbind
udp        0      0 :::993                      :::
*                                    4634/rpcbind
udp        0      0 :::111                      :::
*                                    4634/rpcbind
unix  2      [ ACC ]     STREAM     LISTENING     17222
4634/rpcbind        /var/run/rpcbind.sock


Everytime I restart rpcbind , a new port under 1024 is opened.
Why is rpcbind opening an additional port under 1024 and what is the purpose of this port?
Comment 2 Steve Dickson 2017-04-08 15:47:29 UTC 
(In reply to divya.n.gopi from comment #0)
> Description of problem:
> rpcbind not only listens to the tcp port 111 and UDP port 111, but to an
> undocumented UDP port.
> 
> Steps to Reproduce:
> 
> Everytime I restart rpcbind , a new port under 1024 is opened.
> Why is rpcbind opening an additional port under 1024 and what is the purpose
> of this port?

That port is used for remote calls...