2 Jul 2009 20:20
Re: connection reset by server
NoOp <glgxg <at> sbcglobal.net>
2009-07-02 18:20:13 GMT
2009-07-02 18:20:13 GMT
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 (184.108.40.206) 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: $ 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  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.