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merlijn
Apprentice
Joined: 10 Apr 2007
Posts: 161
Location: Den Haag, Holland
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 Posted: Wed Jul 18, 2007 1:43 pm Post subject: Problems setting right MTU in /etc/conf.d/net |
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For some reason it seems the mtu_eth0 setting has no effect in my case, I want to have it at 9000 for my home gigabit lan. Everytime I reboot it prompts the message "Given MTU 64 is too low, setting MTU to 576". Hrm, didnt i say 9000?
/etc/conf.d/net
| Code: |
modules=( "ifconfig" )
config_eth0=( "dhcp" )
mtu_eth0="9000"
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DHCP comes from my rather old adsl router, which only has a 100 mbit connection to the gigabit switch' uplink.
Any input would be much appreciated. |
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steveb
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Joined: 18 Sep 2002
Posts: 4564
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| Posted: Wed Jul 18, 2007 3:01 pm Post subject: |
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It could be that your NIC does not allow 9000 (jumbo frames) or your router/switch/whatever. What NIC are you using?
// SteveB |
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merlijn
Apprentice
Joined: 10 Apr 2007
Posts: 161
Location: Den Haag, Holland
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| Posted: Wed Jul 18, 2007 3:24 pm Post subject: |
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Thank you for your reply.
The card is an onboard controller based on Realtek RTL8111B. I always thought 9000 as mtu was the standard for gigabit connectors (or the standard maximum to put it better) isn't jumbo frames mtu 15000 for gigabit?
I am not very sure about my network equipment. The switch is fully gigabit capable and should handle every mtu, but the router is old and shitty, and is based on only 10/100mbit ethernet, how would this affect the mtu settings?
Cheers, |
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steveb
Advocate
Joined: 18 Sep 2002
Posts: 4564
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| Posted: Wed Jul 18, 2007 10:51 pm Post subject: |
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| merlijn wrote: | | The card is an onboard controller based on Realtek RTL8111B. I always thought 9000 as mtu was the standard for gigabit connectors (or the standard maximum to put it better) isn't jumbo frames mtu 15000 for gigabit? |
Okay. You have a problem. The RTL8111B does indeed support jumbo frames but the driver included in the stock Kernel has a problem with it (not only with jumbo frames. Even normal 1500 MTU can be a problem with the driver in the stock Kernel). You need to go to Realtek web page and download the driver from there and patch your current Kernel with it. This will allow you to set jumbo frames.
| merlijn wrote: | | I am not very sure about my network equipment. The switch is fully gigabit capable and should handle every mtu, but the router is old and shitty, and is based on only 10/100mbit ethernet, how would this affect the mtu settings? |
This can affect MTU settings. You need to check if your router supports jumbo frames. If it does not support jumbo frames then check if it supports baby frames (this is around 6000 MTU).
Check here for the working driver.
// SteveB |
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