James Knott wrote:

James Knott wrote:

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I recently upgraded my firewall from 11.0 to 11.3 and one thing I've noticed is routing performance is much worse. I have a 10 Mb/s download via cable modem and regularly achieved that with my old firewall. However, with 11.3, I'm barely able to reach 5 Mb/s. I even increased the memory of that computer, from 128 MB to 512, but no difference. Any idea what might be causing this? A D-Link router also delivers full performance, so it's not a cable modem issue.

tnx jk

Found the problem. I had to manually set the MTU on the interfaces to 1500.

What was the MTU set as? 1500 is the default. -- Per Jessen, Zürich (-4.4°C) -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

James Knott wrote:

Per Jessen wrote:

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What was the MTU set as? 1500 is the default.

It wasn't set to anything.

The interface must have had at least the default value though. Weird problem. -- Per Jessen, Zürich (-0.9°C) -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

Tony wrote:

+1

Thanks, this solved a slow router issue on a 11.1 box

Very odd for sure

I don't recall it happening on my 11.0 firewall. I wonder what changed and why the default 1500 no longer works? -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

phanisvara das wrote:

On Tue, 30 Nov 2010 23:40:31 +0530, James Knott wrote:

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I don't recall it happening on my 11.0 firewall. I wonder what changed and why the default 1500 no longer works?

i think it depends on the infrastructure of your internet provider, what MTU values are supported or not. whatever the default value (if any) is, if it's not 1500, may work in one location and not in another. here in rural india per example i have to set MTU = 1492, otherwise half the www isn't reachable.

I'm on a cable modem and 1500 works fine. Also, this came in with 11.3. I didn't have this problem with 11.0, nor any commercial router/firewall box. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

Per Jessen wrote:

James Knott wrote:

...

Tony wrote:

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+1

Thanks, this solved a slow router issue on a 11.1 box

Very odd for sure

I don't recall it happening on my 11.0 firewall. I wonder what changed and why the default 1500 no longer works?

The default MTU works very well here (new 11.3 vanilla+updates) - I have not tested forwarding speed between two interfaces though, but the default MTU still works fine. Before you set your MTU manually, presumably in /etc/sysconfig/network/ifcfg-ethx, do you know if MTU was set any differently on the interface?

The default also works well on my main computer, which is connected to the firewall via a switch. I used the network settings in Yast to set the two interfaces to 1500. Prior to that, I hadn't set any interface MTU. I've just checked another system where I have not set the mtu and I see this in the ifcfg-eth0 file: MTU=' ' On a system with it set, it has: MTU='1500' ifconfig shows: UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1. As this indicates, the default is 1500. I'll have to do some experimenting, to see which interface is causing the problem. BTW, someone else sent a note saying they also had experienced this problem on an 11.1 router. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

James Knott wrote:

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I'll have to do some experimenting, to see which interface is causing the problem. I just tried editing the ethx file for the interface connected to the cable modem. If I remove the setting for mtu and restart networking,

James Knott wrote: the problem returns and ifconfig shows an mtu of 576. If I do the same to my local lan interface, the mtu remains at 1500.

IIRC, 576 is the minimum MTU for the internet, there is an RFC for it. I'm wondering if it was set automagically by pmtu discovery, but if 576 is the appropriate value for your cablemodem, setting it to 1500 should have ruined your download rate. -- Per Jessen, Zürich (-2.4°C) -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org