performance troubles

performance troubles

[Stefan Mueller]

Hello
i have a performance problem with my new SNAT (masquerade).
i have a cable modem with 512kbit/s. downloading a 1MB file takes 30s without 
NAT. downloading the same file from a pc behind NAT takes 500s! (2.5kbit/s)

OK, some information:
the NAT Router:
-AMD 1800+
-512MB DDR-Ram
-10MBit Card to the Cablemodem (the cabelmodem has a 10Mbit connector)
-100MBit to the Intranet
-Redhat 8.0 (2.4.18-14)
-iptables v1.2.6a
-load average 0.00 0.00 0.00
-no entrys in /var/log/messages
-iptables -L -> nothing,policy ACCEPT in INPUT OUTPUT FORWARD
-using iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
-interfaces:
 eth0 217.162.74.155 mask 255.255.254.0 (dhcp)
 eth1 10.22.0.1      mask 255.255.0.0
-routing table:
 217.162.74.0 *              255.255.254.0 U  0 0 0 eth0
 10.22.0.0    *              255.255.0.0   U  0 0 0 eth1
 127.0.0.0    *              255.0.0.0     U  0 0 0 lo
 default      (isp's router) 0.0.0.0       UG 0 0 0 eth0

the Client
-AMD 1800+
-512MB DDR-Ram
-100MBit to the Intranet
-Redhat 8.0 (2.4.18-14)
-load average 0.00 0.00 0.00
-iptables v1.2.6a
-no entrys in /var/log/messages
-iptables entrys
-interfaces:
 eth0 10.22.32.1 mask 255.255.0.0
-routing table:
 10.22.0.0 *         255.255.0.0 U  0 0 0 eth0
 127.0.0.0 *         255.0.0.0   U  0 0 0 lo
 default   10.22.0.1 0.0.0.0     UG 0 0 0 eth0

transmission between server and client has normal 100Mbit speed.
ping from the client to the internet is normal at ~100ms

what did i wrong? i know that NAT can't be as fast as a direct connection but 
this is terrible slow...
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Open WebMail Project (http://openwebmail.org)

Re: performance troubles

[Stefan Mueller]

I found the problem my self, it wasn't the NAT, it was the 10Mbit Card. This 
card was defect. Now NAT works just great!

-Stefan Mueller

> Hello
> i have a performance problem with my new SNAT (masquerade).
> i have a cable modem with 512kbit/s. downloading a 1MB file takes 
> 30s without NAT. downloading the same file from a pc behind NAT 
> takes 500s! (2.5kbit/s)
> 
> OK, some information:
> the NAT Router:
> -AMD 1800+
> -512MB DDR-Ram
> -10MBit Card to the Cablemodem (the cabelmodem has a 10Mbit 
> connector) -100MBit to the Intranet -Redhat 8.0 (2.4.18-14) -
> iptables v1.2.6a -load average 0.00 0.00 0.00 -no entrys 
in /var/log/messages
> -iptables -L -> nothing,policy ACCEPT in INPUT OUTPUT FORWARD
> -using iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
> -interfaces:
>  eth0 217.162.74.155 mask 255.255.254.0 (dhcp)
>  eth1 10.22.0.1      mask 255.255.0.0
> -routing table:
>  217.162.74.0 *              255.255.254.0 U  0 0 0 eth0
>  10.22.0.0    *              255.255.0.0   U  0 0 0 eth1
>  127.0.0.0    *              255.0.0.0     U  0 0 0 lo
>  default      (isp's router) 0.0.0.0       UG 0 0 0 eth0
> 
> the Client
> -AMD 1800+
> -512MB DDR-Ram
> -100MBit to the Intranet
> -Redhat 8.0 (2.4.18-14)
> -load average 0.00 0.00 0.00
> -iptables v1.2.6a
> -no entrys in /var/log/messages
> -iptables entrys
> -interfaces:
>  eth0 10.22.32.1 mask 255.255.0.0
> -routing table:
>  10.22.0.0 *         255.255.0.0 U  0 0 0 eth0
>  127.0.0.0 *         255.0.0.0   U  0 0 0 lo
>  default   10.22.0.1 0.0.0.0     UG 0 0 0 eth0
> 
> transmission between server and client has normal 100Mbit speed.
> ping from the client to the internet is normal at ~100ms
> 
> what did i wrong? i know that NAT can't be as fast as a direct 
> connection but this is terrible slow...
> --
> Open WebMail Project (http://openwebmail.org)


--
Open WebMail Project (http://openwebmail.org)