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reup
Guru
Joined: 13 May 2005
Posts: 419
Location: Nederland
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 Posted: Fri Jan 04, 2008 1:07 pm Post subject: provider and vpn change mtu |
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hello all,
I am using dhcpcd to set my network in 3 different environment
1 on a laptop, I am at work on the intranet and the dhcp server set my eth0 mtu to 576, I have to enter ifconfig eth0 mtu 1500 to be able to work properly
2 from my laptop, I vpn to another network, and get the cispec0 mtu set to 576 or 1350, and have to run ifconfig to set it to 1500
3 at home, I have my router connected to the provider by cable and dhcpcd to receive a network setting, the mtu keeps reverting to 576 as well. so my laptop gets mtu set again to 576 and have to run ifconfig again on the router and on the laptop
I have tryed 2 setting on the /etc/conf.d/net, found in this forum :
dhcpcd_eth0="-m 1500"
mtu_eth0="1500"
none works
any idea how I can fix my mtu to 1500 and be done with it ?
thanks
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reup
"Don't wiggle the tail of the frog in the oil of the frying peanuts" |
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Dagger
Retired Dev
Joined: 11 Jun 2003
Posts: 765
Location: UK
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| Posted: Fri Jan 04, 2008 1:17 pm Post subject: |
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if your MTU has been set up to 576 every single time it indicates that your problem lies in your settings.
From what I believe (from your vpn settings) your dhcp client has to overwrite default MTU with 576 value (value 1350 is correct for Cisco VPN. You may experience problems if you manually switch it to 1500).
what dhcp client are you using?
also can you please post your /etc/conf.d/net?
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reup
Guru
Joined: 13 May 2005
Posts: 419
Location: Nederland
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| Posted: Fri Jan 04, 2008 1:35 pm Post subject: |
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| Code: | config_eth0=( "dhcp" )
dhcpcd_eth0="-m 1500"
gateway=eth0
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I am using dhcpcd and have speed problem when I use 1350 as mtu in my connection will the problems go away if I set it to 1500
net-misc/dhcpcd-3.0.16-r1
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reup
"Don't wiggle the tail of the frog in the oil of the frying peanuts" |
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reup
Guru
Joined: 13 May 2005
Posts: 419
Location: Nederland
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| Posted: Fri Jan 04, 2008 1:39 pm Post subject: |
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my router is gentoo on amd64
this is the /etc/conf.d/net file
| Code: | # /etc/conf.d/net:
# $Header: /home/cvsroot/gentoo-src/rc-scripts/etc/conf.d/net,v 1.7 2002/11/18 19:39:22 azarah Exp $
modules=( "dhcpcd" )
config_eth0=( "192.168.0.1 broadcast 192.168.0.255 netmask 255.255.255.0" )
config_eth1=( "dhcp" )
dhcpcd_eth1="mtu 1500"
mtu_eth1="1500"
mtu_eth0="1500"
dhcpcd_eth1="-m 1500"
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as you can see, I tried several way to set the mtu
maybe I should use a cron job that would set the mtu every 10 minutes ? I am sure their is a better way to do it
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reup
"Don't wiggle the tail of the frog in the oil of the frying peanuts" |
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Dagger
Retired Dev
Joined: 11 Jun 2003
Posts: 765
Location: UK
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| Posted: Fri Jan 04, 2008 11:41 pm Post subject: |
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can you try upgrading dhcpcd to 3.1.5-r1 (latest stable) and check if you experience the same problem?
Also try changing dhcpcd for dhclient and check the result.
I've got the impression I've seen this problem before and my memory is good (but short :p) and I can't remind myself...
EDIT:
check this out and check MTU on your gentoo router. How is it connected to the internet?
about the cisco VPN... try using through scp or sftp with MTU 1500. it will hand the connection after a while. Also FTP wont work correctly and such. I had really hard time with cisco VPN and backup scripts sending data over it.
you mentioned cron job for setting MTU 1500. Does it reset it every few minutes to 576?
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