[CentOS] CentOS-6 firewall how to open a port

Timothy Murphy gayleard at eircom.net
Sun Jul 17 15:39:03 UTC 2011

I'm running CentOS-6 on an HP MicroServer (since this morning)
and I'd like to open an non-standard port,
for use on a laptop  attached to the internet through the server.

Do I have to explicitly add an iptables rule?
If so, and I want to open (say) udp port 500 ,
what command should I give?

I've always used shorewall in the past,
and will probably do so now if the default firewall is difficult to use.
But I thought I would try it first as an experiment.

My recollection is that in old versions of CentOS
one could non-standard ports through system-config-firewall ;
but it seems that now this can only be used for standard ports;

I looked at <http://wiki.centos.org/HowTos/Network/IPTables>
but didn't find it very enlightening.

Any advice or suggestions gratefully received.

Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

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