connection reset by server

[Jay Daniels]

NoOp wrote:
> On 06/30/2009 05:39 PM, Jay Daniels wrote:
>> Seems to only happen on certain sites repeatedly at times and at random. 
>>   However, while browsing using hardy and firefox I've been getting a 
>> lot of these.
>>
>> Connection reset by server...
>>
>> Shoddy satellite connection; however, I was wondering if there is an MTU 
>> or some other setting on the Linksys I could set to get rid of this 
>> problem?  I believe it set to standard 1500.
>>
>>
>> jay
>>
> 
> You can test for when fragmentation starts:
> 
> ping -M do -s 1460 google.com
> 
> and you should get normal ping. That setting is MTU (Maximum
> Transmission Unit - the maximum packet size for the link) 1488
> (1460+28). Now adjust 1460 higher until you hit something like:
> 
> $ ping -M do -s 1465 google.com
> PING google.com (74.125.45.100) 1465(1493) bytes of data.
>>From <machine> (192.168.4.100) icmp_seq=1 Frag needed and DF set (mtu =
> 1492)
> 
> So if I set my MTU higher than 1492 (1464+28) to 1493 (1465+28) I run
> into fragmentation issues.
> 
> The default MTU set in Ubuntu is 1500 (it is set that way because
> Ethernet has a maximum payload size of 1500 octets). However because my
> DSL is using PPoE, my router and my dsl modem are set for 1492 per RFC
> 2516 (RFC2516 - A Method for Transmitting PPP Over Ethernet (PPPoE)). So
> it makes no sense to have my client MTU(s) set at 1500[1]:
> 
> $ tracepath google.com
>  1:  <machine> (192.168.4.100)   0.177ms pmtu 1500 <=== this is when I'm
> set to the default 1500
>  1:  192.168.4.1 (192.168.4.1)   0.534ms pmtu 1492 <=== this is telling
> me that my router set to 1492 per RFC 2516
> 
> So I can temporarily change the MTU on the client to 1492:
> 
> $ sudo ifconfig eth0 mtu 1492
> 
> And I now match my router:
> $ tracepath google.com
>  1:  <machine> (192.168.4.100)           0.175ms pmtu 1492
>  1:  192.168.4.1 (192.168.4.1)           0.564ms asymm 106
> 
> If I wish to change eth0 to 1492 permanently:
> 
> $ gksu gedit /etc/network/interfaces
> 
> and at the bottom of my iface secton I add 'mtu 1492':
> 
> iface eth0 inet static
> address 192.168.4.100
> netmask 255.255.255.0
> gateway 192.168.4.1
> mtu 1492
> 
> If you are using DHCP, I _think_ it's something along the lines of:
> 
> iface eth0 inet dhcp
> pre-up /sbin/ifconfig $IFACE mtu 1492
> 
> 
> [1] I only have a small local network, so I'm not concerned about the
> difference between a 1500 MTU vs 1492 MTU  on the ethernet between
> machines.
> 
> 
> 

Oh man, that some good info!

It's late, but me saving this message...

later,


jay