[ale] PPP Perfromance

Geoffrey esoteric at 3times25.net
Fri Oct 31 10:54:19 EST 2003


Doug McNash wrote:
> 
> 
> Some network traffic can't be fragmented but I am drawing a blank right 
> now as to what besides ICMP that traffic is.
> Packets get fragmented if they enter a network segment that has an MTU 
> smaller than the packet size. There is a DO_NOT_FRAGMENT flag which if 
> set causes the packet to be dropped and and ICMP UNREACHABLE error to be 
> sent back if fragmentation is required somewhere along the line.  

Getting back to the mtu issue, I'm now curious as to whether that might 
be part of the problem why I couldn't get to my mother-in-laws benefit 
web site.  I've played with mtu a bit and found a couple things out. 
Currently all my ethernet networks are set at mtu 1500.  I can easily 
reduce this by simply:

ifconfig eth0 mtu 1000

But if I attempt to increase it, I get an error.  Me thinks this would 
because there's a max set somewhere, although after running around in 
/proc for a while, I couldn't find anything.  Anyone else have any ideas?


-- 
Until later, Geoffrey	esoteric at 3times25.net

Building secure systems inspite of Microsoft



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