AW: bandwidth problems [Linux 2.4.20] [iptables 1.2.7a]

[<root@scheuchenstuel.com>]

> > Hi!
> >  
> > My configuration:
> > =================
> > 
> > O-------------o    O-----------------------o
> > |    WinXP    |    |    eth0     |   eth1  |
> > | 10.10.1.100 |----| 10.10.1.254 | D H C P |----INTERNET
> > |             |    |             |         |
> > O-------------o    O-----------------------o
> >   My Computer           My NAT-Computer
> > 
> > NAT-Computer:
> >   Linux 2.4.20-4GB
> >   load average: 0.08, 0.05, 0.06
> >   iptables v1.2.7a
> > All the NICs I use are 3com 3C905-TX
> > 
> > When I do some bandwidth tests on the NAT-Computer 
> (provider's service 
> > page) my bandwidth is about 1MBit/second When I do the same on my 
> > computer I only get about 100kbit/second
> > 
> > Now I wonder if there are any problems with my configuration...?
> > Would be nice if you could help me...
> > 
> > Thanks in advance
> > Florian St.
> > 
> > Root(AT)scheuchenstuel(DOT)com
> > 
> > 
> > My iptables-configuration:
> > ==========================
> > 
> > 
> ######################################################################
> > ######
> > ######
> > 
> > #!/bin/bash
> > #
> > 
> > modprobe iptable_nat
> > echo 1 > /proc/sys/net/ipv4/ip_forward
> > 
> > ########## CLEARING TABLES
> > iptables -F
> > iptables -t nat -F
> > iptables -t mangle -F
> > iptables -X
> > 
> > ########## SETTING POLICIES
> > iptables -P INPUT DROP
> > iptables -P OUTPUT ACCEPT
> > iptables -P FORWARD DROP
> > 
> > ########## NAT
> > iptables -A INPUT -i eth1 -m state --state ESTABLISHED,RELATED -j 
> > ACCEPT iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE
> > 
> > ########## LOOPBACK SETTINGS
> > iptables -A INPUT -i lo -j ACCEPT
> > iptables -A INPUT -s 127.0.0.1/32 -j ACCEPT
> > 
> > ########## EXTERNAL OPEN PORTS
> > iptables -A INPUT -i eth1 -p tcp --dport 80 -j ACCEPT
> > 
> > ########## INTERNAL OPEN PORTS
> > iptables -A INPUT -s 10.10.1.100/32 -j ACCEPT
> > 
> > ######### NAT FORWARDING
> > iptables -A FORWARD -s 10.10.1.100/32 -j ACCEPT iptables -A 
> FORWARD -d 
> > 10.10.1.100/32 -j ACCEPT
> > 
> > 
> ######################################################################
> > ######
> > ######
> 
> The rules look a little unusual; in fact, they look downright 
> dangerous.  You may want to read a good iptables tutorial 
> such as the one by Oskar Andreasson.  You can find a link to 
> it on the netfilter.org web site.  You can also find some 
> slide shows in the training section at http://iscs.sourceforge.net 
> 
> However, I do not think your rules would create a throughput problem. 
> How are you measuring your throughput?
> --
> John A. Sullivan III
> Chief Technology Officer
> Nexus Management
> +1 207-985-7880
> john.sullivan@nexusmgmt.com
> ---
> If you are interested in helping to develop a GPL enterprise 
> class VPN/Firewall/Security device management console, please 
> visit http://iscs.sourceforge.net 
> 

Now i tried to use a script sufggested by Oskar Andreasson
http://iptables-tutorial.frozentux.net/iptables-tutorial.html#RCFIREWALLTXT

But the problem is still the same...
I think there is another problem...

When i configure&start squid on the NAT-Computer i have full bandwidth...

I don't know what to do anymore...

Thanks in advance
Florian St.