Firewall

Use iptables. Configure using sample below.

# Generated by iptables-save v1.2.8 on Fri Feb 3 06:20:08 2006
*mangle
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
COMMIT
# Completed on Fri Feb 3 06:20:08 2006
# Generated by [...]

CVS

Install CVS via yum.
Setup the listening port.
Make sure the following lines exist in /etc/services

cvspserver 2401/tcp

Create file named cvspserver under /etc/xinetd.d with the following contents:

service cvspserver
{
socket_type = stream
protocol [...]