I've got a small LAN with M$ W98 peer-peer PCs running NetBEUI and a dial-up ISDN router providing internet access.
The router (D-Link DI-106) also provides a DHCP Server so I don't assign static IPs to the PCs cos the router does that dynamically - the only static IP which is set in each PC is that of the router as 'TCP/IP Gateway'.

I've now added a Red Hat 7.2 box. The only server function of this box will eventually be for Telenet/Ssh.
When I installed RH I gave it a static IP address (within the router's DHCP range) and now I can't seem to change or remove that address. I can ping in to the RH box using the original IP but if I change the IP in /etc/hosts, I can't ping in with the new IP. I've tried stopping and starting the network via /etc/rc.d/init.d/network but it makes no difference. /etc/dhcp/dhcpcd-eth0.info always shows the original IP.

a) Should it be necessary for the RH box to be assigned a Static IP when the router operates as DHCP Server?
The RH Network Config (neat) is set up to "Automatically obtain IP address settings with dchp" and the Static IP settings are blanked-out.

b) Will any use of static IPs interefere with the DHCP service? eg: will they reduce the security benefit of DHCP?

to make the box dhcp and not static edit /etc/sysconfig/network-scripts/ficfg-eth0 and change the PROTO=statis th PROTO=dhcp. you should alos remove the other lines about NETMASK's and such like, leaving you with just:

DEVICE=eth1
ONBOOT=yes
BOOTPROTO=dhcp

sould be all you need to do.

be careful abuot /etc/hosts, that file is just used as a lookup for ip addresses for pinging, sshing, www etc... there's nothign wrong with adding in any other addresses in there, but changing your own can cause inconsistency problems, ep if you touch teh localhost line.