星期四 2008年07月10日 vpnclient issues caused by small mtu
I upgraded my system to the last version. Then the vpnclient stop work. It will failed at Authenticating user.Negotiating security policies. I spent some time fighting on it. I found out if caused by the small MTU of my interface.
For some reason my wireless router's dhcp server return a very small mtu 576. I can make vpnclient work my manual increase the mtu value to the general ethernet interface mtu 1500 by:
ifconfig eth0 mtu 1500
And I changed the following settings to set the interface mtu to 1500 at system boot.
1. set mtu to 1500 before interface up
add the following to /etc/network/interfaces after iface eth0 inet dhcp:
pre-up /sbin/ifconfig $IFACE mtu 1500
If you are using static ip instead of dhcp you can direct put mtu 1500 bellow your iface line. And you can skip next step.
2. Avoid dhcp client set the interface mtu
Find the following line in /etc/dhcp3/dhclient.conf and remove interface-mtu.
Before modify:
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-name-servers, domain-search, host-name,
netbios-name-servers, netbios-scope, interface-mtu;
After modify:
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-name-servers, domain-search, host-name,
netbios-name-servers, netbios-scope;
That's all. Try it if you have this issue too. And please kindly let me know whether it works for you.
Thanks
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My Tags: cisco
( 2008年07月10日, 09:30:13 下午 CST ) [Listen] Permalink 评论 [0]
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