Hello everybody .
I want to build a *nix based router/dhcp server to handle a big LAN (the number of machines may up to 6000 or more) the bandwidth discounted may up to 100 Mbps or maybe more ,here is a little schema :

/~~~~~\
|Internet|
\~~~~~/
|
|(POS interface 150 Mbps)
[Cisco7500 router ]
|(GigaBit interface)
|
|
|eth0 (1000 baseT ethernet)
[my *NIX machine]
|eth1 (1000 baseT ethernet)
|
|
/~~~~~\
|MyLAN |
\~~~~~/
this *NIX server has to allocate IPs for my LAN and also it has to route all trafic between the cisco router and the lan .

for that i want to know what's the BEST *NIX to use for that task i have already many choices but don't know what to choose between a linux distro with some tunning , a *BSD or a specialisez distro like smoothwall or LinuxRouter . all advices are welcome
and thank's from the advance

ipcop.

You have to be kidding me littleking. IPCop is not designed as an enterprise-grade solution, it's very much targeted for SoHo environments.

freelinuxcpp, to answer your question, either a Linux distro or a BSD could do what you want. A micro-distro is unlikely to suite your needs since most of them (like Smoothwall, IPCop, etc) are designed for SoHo environments and don't have the flexibility and control you'll need.

Of course, the most important thing is knowing how to configure the various TCP/IP services properly. A 6,000 station LAN is huge. Depending on the default values your choice of OSs has, you may need to tweak SYN buffers, timeout values, etc.

Another consideration is whether you're going to need to do any packet filtering on the box. The various Open Source packet filters all have different capabilities and differing learning curves. The BSD packet filters have natural-language syntax, while netfilter/iptables has a quirky command line option syntax.

I'm going to move this to the Enterprise section since it's a lot more relevant there.

ok thank you very much for ur anwers ,
i ll try to setup a nasic debian sid with a latest kernel , some tunning here is needed , but this depend on the trafic i m going to have , i ll leave the default kernel value , and increase them if needed , i think a 2.6 is gonna do the job well
thnx again