renewal of ip address by dhcp

Hi,
what's the Linux command to force the renewal of the IP address by DHCP on a
eth interface? (the equivalent of ipconfig /release, ipconfig /renew of
ms-windows).
I have two routers on different subnetworks and frequently need to
plug/unplug the ethernet adapter of my linux box from one router to the
other.

I have tried the following commands:
ifconfig eth0 down && ifconfig eth0 up
but when eth0 is up again it still has the old address.

Didn't find anything in the man page of ifconfig.

Thank you!

"Belga" <(E-Mail Removed)> wrote in message
news:422f89a8$0$18759$(E-Mail Removed)...

> what's the Linux command to force the renewal of the IP address by DHCP on
a
> eth interface?

man -k dhcp