---------- Original Message ---------------------------------- From: Ric Moore wayward4now@gmail.com Reply-To: CentOS mailing list centos@centos.org Date: Tue, 09 Sep 2008 14:56:58 -0400
On Mon, 2008-09-08 at 23:46 -0600, Joseph L. Casale wrote:
I have a server with dual nic's running centos 5.2 1 nic connects to the cable modem, which has 15m d and 2m up, but speed tests barely come back at 5mb down including road runner's internal speed test. I hook up my laptop to the same modem, same port, using the same cable and I get 17mb down. I have ruled out iptables, nics (because same result on both nics), cables, cable modem(with a brighthouse rep) any suggestions would be greatly appreciated. Thanks.
So I gather the nics aren't teamed from your wording, maybe MTU is set sub optimal for your particular ISP? What OS on your laptop? Wrong MTU can have a significant effect such as this.
"Back in the day..." there used to be a utility that would test your connection for the optimal MTU setting. Is there something like that for Linux?? Ric
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I got my information about the MTU setting from doing google searches and the message boards on broadband reports as well as doing the tweak test on broad band reports.
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I got my information about the MTU setting from doing google searches and the message boards on broadband reports as well as doing the tweak test on broad band reports.
It appears you are on Comtrash where everything is CoMtRaSHtIc.
Good for you. Dance a jig.
Stop beating the MTU horse to death and get busy finding out how to best connect to the CPE devices.
Google that stuff.
First, when testing, disable (admin down) the internal network on the second nic
Also, check to see what specific nics you have an if any recent issues with kernels and such and any updates.
Google that too.
Then Focus on the internet transit/transport infrastructure.
Find out best way to interface with the cable modem CPE infrastructure.
Meaning what speed and duplex.
Trial and error.
You will get there...
Some nics need to be played with and dealt with in terms of kernel and other things like disable ipv6 in modprobe.conf and dhcp...
You might be better off having an intermediate device between you and the cable modem if your nics don't wanna play nice with the cable modem.
Last but not least, you can always check stats and see if collisions and errors on interfaces and more.
Enjoy
- rh
I got my information about the MTU setting from doing google searches and the message boards on broadband reports as well as doing the tweak test on broad band reports.
David
I also noticed that if you
dig dlsi.com
it appears to come up as 0.0.0.0
huh?
Good for you.
maybe you should change that depending on how you have things setup
could be that your packets get a lil confused eh?
- rh
David Petruzzella wrote:
I got my information about the MTU setting from doing google searches and the message boards on broadband reports as well as doing the tweak test on broad band reports.
MTU's need to match the lowest value in the path between endpoints not just your adjacent connection. If there are tunnels/PPOE that add encapsulating headers involved you'll have a performance hit when the routers need to fragement and reassemble large packets.
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David Petruzzella -
Les Mikesell -
RobertH