Did you configure it in the initial install? Check /etc/resolve.conf and put network nameservers here. Also check /etc/conf.d/net. I've attached an exaple below. For your local LAN, you likely will want to set your box up as static IP (or DHCP if need be)
Other than that, you need to make you networking start at boot via init or rc-scripts. I cannot comment on that because it is Mandrake specific, but you should be able to find it easily.
Have Fun~!
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/etc/conf.d/net EXAMPLES
(For DHCP)
iface_eth0="dhcp"
# Some network admins require that you use the
# hostname and domainname provided by the DHCP server.
# In that case, add the following to let dhcpcd use them.
# That will override your own hostname and domainname definitions.
dhcpcd_eth0="-HD"
# If you intend on using NTP to keep your machine clock synchronized, use
# the -N option to prevent dhcpcd from overwriting your /etc/ntp.conf file
dhcpcd_eth0="-N"
(For static IP)
iface_eth0="192.168.0.2 broadcast 192.168.0.255 netmask 255.255.255.0"
gateway="eth0/192.168.0.1"
(For rp-pppoe)
iface_eth0="up"
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