Loss of ethernet link after DHCP release

Greetings.

A linux box (2.4.18) is connected to a cable modem through a small
5-port switch. Can launch it smoothly on line with dhcpcd -d.

The problem is, after releasing the DHCP lease manually with dhcpcd -k,
the box loses its ethernet link to the switch. No LED on the attached
switch port though the NIC still has its LED on. As if the switch had
been turned off, which of course isn't. And ifconfig shows the
interface is present and up. Just couldn't run dhcp -d again to get it
on line. All I have to do is to reboot the machine and start dhcpcd -d
automatically or manually once more.

Also, nothing output from tcpdump. In normal circumstances, even if the
NIC is assigned a private IP in the absence of DHCP control, tcpdump
would dispay a lot of ARP messages from the cable modem.

Anyone experiences something similar before?

Thanks.