On Tue, 2007-11-13 at 11:54 -0500, Ross S. W. Walker wrote:
3 possible scenarios:
- DNS not properly configured
Make sure your resolv.conf is properly configured, if you are doing DHCP look into having your resolv.conf set through it, if you are using PPPOE you can have the ppp daemon set it too if the DNS is passed over the ppp connection.
Don't have a resolve.conf.
- TCP MTU and blackhole router if PPPOE
If you are doing PPPOE then make sure the MTU on the ppp interface link is set to 1492 as pppoe uses 8 bytes for ppp framing. If it is set to 1500 then some large packets will drop and the stack will have to resend smaller and smaller till it goes through. If ICMP need to frag messages are dropped then the connections will stall completely.
1492, by default.
- TCP scaling window and broken router
The latest CentOS uses the TCP scaling window algorithm to the RFC spec which some routers don't support. Some people have noticed that this solves the problem when communicating to other hosts over the Internet.
sysctl -w net.ipv4.tcp_window_scaling=0
I tried it - will see. BTW, this wouldn't muck up my keyboard shortcuts, would it? I noticed that after I executed this, some of them stopped working - again.
mhr