DHCP

[Constantine]

Hello!

I have a FreeBSD box with 2 Ethernet cards, win xp notebook, a DSL-modem 
ZyXEL P645ME+, and a switcher.
First I connected the modem directly to win xp, the internet was working.
Then I connected FreBSD and the modem to the switcher (I don't have a 
free crossover cable. Nothing else was connected to that switcher at the 
time), and win xp to the FreeBSD. The internet was not working on the 
FreeBSD, though after manually running "ifconfig sis0 192.168.1.18 
netmask 255.255.255.252" I could connect to the modem itself, but not to 
the internet (by default sis0 is set to the DHCP, and the modem supports 
DHCP, but it does not seem to give an address to the FreeBSD).

Question 1:
After I have made a few changes to the settings on the FreeBSD box, and 
restarted the system, I cannot connect to my FreeBSD box anymore. Is 
there a way to connect to the FreeBSD box, if the network addresses got 
messed up? One of the interfaces should be set to the DHCP, so is there 
a way, or an utility for win32 (cygwin, or just windows) to get back my 
access to the box, or will I need to borrow a monitor to fix that up?

Question 2:
And the second question is, why the modems DHCP server was not assigning 
the address to the FreeBSD? Could it be, because it was connected 
through a switcher? Now my win xp is connected through the same switcher 
to the same modem, and everything works fine...

Just for a reference, these are a few lines that should be in my 
rc.conf. I was playing with the gateway, natd, and that kind of 
features, and after restarting I can no longer ping the box through the 
fxp0 interface with the address stated above.
ifconfig_sis0="DHCP"
ifconfig_fxp0="inet 192.168.0.18  netmask 255.255.255.0"
gateway_enable="YES"

Thank you for reading this letter,
Constantine.