LinuxQuestions.org - [SOLVED] rpc.rquotad is using port number 993

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- - rpc.rquotad is using port number 993 (https://www.linuxquestions.org/questions/linux-server-73/rpc-rquotad-is-using-port-number-993-a-720885/)

rpc.rquotad is using port number 993

I have just uncommented the line in the /etc/dovecot.conf

Code:

protocols imaps imap pop3 pop3s

.

In /etc/exports;
I just exported a directory

I did start the nfs service & portmap service without any problem. But; when i tried to start the dovecot service; the following error occurred.

Code:

Stopping Dovecot Imap:                                    [FAILED]

Starting Dovecot Imap: Fatal: listen(993) failed: Address already in use

                                                          [FAILED]

On running the netstat -tanp | grep 993 command; i got the following output ->

Code:

tcp        0      0 0.0.0.0:993                0.0.0.0:*                  LISTEN      2485/rpc.rquotad

This output is baffling me.
I am unable to understand; why rpc.rquotad is using 993 port?

Quote:

Originally Posted by Mr. ameya sathe (Post 3517164)

I have just uncommented the line in the /etc/dovecot.conf

Code:

protocols imaps imap pop3 pop3s

.

In /etc/exports;
I just exported a directory

I did start the nfs service & portmap service without any problem. But; when i tried to start the dovecot service; the following error occurred.

Code:

Stopping Dovecot Imap:                                    [FAILED]

Starting Dovecot Imap: Fatal: listen(993) failed: Address already in use

                                                          [FAILED]

On running the netstat -tanp | grep 993 command; i got the following output ->

Code:

tcp        0      0 0.0.0.0:993                0.0.0.0:*                  LISTEN      2485/rpc.rquotad

This output is baffling me.
I am unable to understand; why rpc.rquotad is using 993 port?

This does not happen normally, what you can try is
- first stop nfs service
- verify whether 993 is port is freed or not
- start dovecot service
- start nfs service

I think this will work.

from the man page on BSD

"The port that the service is made available on can be specified using the nfs.server.rquota.port option in nfs.conf(5)."

The man page for my linux distribution does not mention this, it only mentions using the -p flag to specify an arbitrary port.

nfs uses random ports unless you tell it to use fixed ports. Indeed you can configure your own port numbers in your sysconfig/nfs (your nfs config file)

Quote:

Originally Posted by vikas027 (Post 3517444)

This does not happen normally, what you can try is
- first stop nfs service
- verify whether 993 is port is freed or not
- start dovecot service
- start nfs service

I think this will work.

It worked. But; it has given rise to few more fundamental questions.

1) So; does this means; that NFS service is so brazen; that it would use even the IANA port assignments.
in the name of random assigning of the ports.?

Following statement is found in RFC 1700.

Quote:

Portmap does not allocate ports, the kernel allocates ports. The code
that does this is part of nearly every UNIX system in the world (and
since the BSD code is 'free' it is often the same code). RPC services
ask the kernel to allocate them a port by calling the "bind()" system
call. The parameter they pass is "INADDR_ANY" which means "allocate
me any IP port you want". The kernel does that by looking at all of
the ports that are currently in use and picking one that is not
currently used. The number picked is either less that 1024 if the
process is privledged, or greater than 1024 if the process is not
privledged. After the kernel has allocated a port, the service
registers this allocation with portmap. The portmapper is merely a
registry of previously allocated ports. Note "allocated" here is
being used in the sense that they are used by an open socket, not
assigned a well known name.

This statement has amazed me:eek:. It means; next time; whenever I want to start any new service in my system.

- first stop portmap service

- verify whether the assigned port is freed or not

- start new service

- start portmap service.

Any other opinions are welcome. :)

I'm a bit late on replying, but this thread was recently referenced in a support post elsewhere, so I thought the information could be useful here. Have a look at http://rlworkman.net/howtos/NFS_Firewall_HOWTO for some discussion on binding NFS-related stuff to specific ports.