[CentOS] OT: Slow browsers or slow connections?

Mark Hull-Richter mhullrich at gmail.com
Wed Nov 14 19:47:33 UTC 2007

On Tue, 2007-11-13 at 11:54 -0500, Ross S. W. Walker wrote:

> 3 possible scenarios:
> 1) 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.

> 2) 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.

> 3) 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.


More information about the CentOS mailing list