[Techtalk] no gateway, yet it works!

[L J Laubenheimer]

Carla Schroder wrote:
> OK, here's a fun lil mystery. Nowhere can I find a gateway setting on my home 
> network- I have a little Linksys NAT firewall box. The gateway is 
> 192.168.1.1, how original, but none of the client PCs have a gateway assigned 
> to them. I've looked in every config file I can find:
> -redhat-config-network, the GUI configurator
> -/etc/sysconfig/network- empty
> 
> ifconfig shows no gateway. so why does it work? I have Internet and DHCP and 
> everything, how in de hell do the client PCs find the Linksys box???
> 
> I thought I knew this stuff......

If the LinkSys box is doing DHCP inside your network (i.e. your systems all 
have dynamic addressing), then the DHCP request/ack handles it.  The DHCP 
client software looks for a DHCP server on any network it's connected to, and 
gets its IP, netmask, and gateway from the DHCP server (the LinkSys box).

The LinkSys box apparently sends out queries along any connection that is 
"live" (i.e. the lights are lit).  If it finds a network card, it listens on 
that port for a DHCP request.  On bootup, your system sends a DHCP request out 
on its primary interface (i.e. eth0).  Handshake, and you're connected.  If 
the answer back is a fixed address, then the LinkSys box lets that override, 
as long as the address is not in its DHCP range.

At least that's how I've understood it.  And don't get me started about 2.4 
kernels and automatic DHCP... it doesn't work.

					Linda
-- 
Linda J Laubenheimer - UNIX Geek, Sysadmin, Bibliophile and Iconoclast
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