Mmmm........ I think you can keep your current 2.4.X kernel, take a look at these options (from a 2.4.26 kernel, don't know if 2.4.27 has these):
Kernel level IP autoconfiguration
CONFIG_IP_PNP
This enables automatic configuration of IP addresses of devices and
of the routing table during kernel boot, based on either information
supplied on the kernel command line or by BOOTP or RARP protocols.
You need to say Y only for diskless machines requiring network
access to boot (in which case you want to say Y to "Root file system
on NFS" as well), because all other machines configure the network
in their startup scripts.
BOOTP support
CONFIG_IP_PNP_BOOTP
If you want your Linux box to mount its whole root file system (the
one containing the directory /) from some other computer over the
net via NFS and you want the IP address of your computer to be
discovered automatically at boot time using the BOOTP protocol (a
special protocol designed for doing this job), say Y here. In case
the boot ROM of your network card was designed for booting Linux and
does BOOTP itself, providing all necessary information on the kernel
command line, you can say N here. If unsure, say Y. Note that if you
want to use BOOTP, a BOOTP server must be operating on your network.
Read <file
ocumentation/nfsroot.txt> for details.
RARP support
CONFIG_IP_PNP_RARP
If you want your Linux box to mount its whole root file system (the
one containing the directory /) from some other computer over the
net via NFS and you want the IP address of your computer to be
discovered automatically at boot time using the RARP protocol (an
older protocol which is being obsoleted by BOOTP and DHCP), say Y
here. Note that if you want to use RARP, a RARP server must be
operating on your network. Read <file
ocumentation/nfsroot.txt> for
details.
Your current 2.4.X kernel should be able to use RARP/BOOTP.
Hope this helps.