Re: Adjusting MTU
On Wed, May 12, 2004 at 02:40:10PM -0400, Ryan Tucker wrote: > I'm trying to find the "Debian Way" to adjust the MTU on an interface... > basically, we have a box behind a firewall which is blocking the ICMP Can't > Fragment packets, and we're sending fairly large data packets through, and, > well, the obvious problem occurs. They can put a little firewall on the LAN > which has an MTU adjustment (and sends the packets back), which fixes the > problem nicely, but that's kinda a hack. the correct solution is to throw out the broken firewall and replace it with something that wasn't made by brain-damaged cretins. if you need some "proof" to get management to throw away the firewall that they "wisely" decided to waste lots of money on, then see the "Blocking ICMP" section of the Common ISP Mistakes document: http://www.freelabs.com/~whitis/isp_mistakes.html this document is fairly old now but is still very relevant - it should be required reading for all ISP tech and management staff. See also "Broken PMTU causes slow networks": http://www.burgettsys.com/stories/56239/ and "PMTU Discovery": http://www.netheaven.com/pmtu.html craig -- craig sanders <[EMAIL PROTECTED]> The next time you vote, remember that "Regime change begins at home"
Re: Adjusting MTU
On Wed, May 12, 2004 at 02:40:10PM -0400, Ryan Tucker wrote: > I'm trying to find the "Debian Way" to adjust the MTU on an interface... > basically, we have a box behind a firewall which is blocking the ICMP Can't > Fragment packets, and we're sending fairly large data packets through, and, > well, the obvious problem occurs. They can put a little firewall on the LAN > which has an MTU adjustment (and sends the packets back), which fixes the > problem nicely, but that's kinda a hack. the correct solution is to throw out the broken firewall and replace it with something that wasn't made by brain-damaged cretins. if you need some "proof" to get management to throw away the firewall that they "wisely" decided to waste lots of money on, then see the "Blocking ICMP" section of the Common ISP Mistakes document: http://www.freelabs.com/~whitis/isp_mistakes.html this document is fairly old now but is still very relevant - it should be required reading for all ISP tech and management staff. See also "Broken PMTU causes slow networks": http://www.burgettsys.com/stories/56239/ and "PMTU Discovery": http://www.netheaven.com/pmtu.html craig -- craig sanders <[EMAIL PROTECTED]> The next time you vote, remember that "Regime change begins at home" -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: Adjusting MTU
The proper solution would be to turn off the DF bit... But I unfortunately have not been able to find it yet... Regards Andrew
Re: Adjusting MTU
The proper solution would be to turn off the DF bit... But I unfortunately have not been able to find it yet... Regards Andrew -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: Adjusting MTU
maybe not the best way, but I have in my /etc/network/interfaces file It puts it all in a place that is easy to find and use auto eth3 iface eth3 inet static address 192.168.1.1 netmask 255.255.255.0 network 192.168.1.0 broadcast 192.168.2.255 up route add -net 192.168.100.0 netmask 255.255.255.0 gw 192.168.1.254 up ifconfig eth3 mtu 500 It may be better to do a pre-up though so it gets done before the interface is brought up auto eth3 iface eth3 inet static address 192.168.1.1 pre-up ifconfig eth3 mtu 500 Chris --- Ryan Tucker <[EMAIL PROTECTED]> wrote: > Greetings... > > I'm trying to find the "Debian Way" to adjust the MTU on an > interface... > basically, we have a box behind a firewall which is blocking the ICMP > > Can't Fragment packets, and we're sending fairly large data packets > through, and, well, the obvious problem occurs. They can put a > little > firewall on the LAN which has an MTU adjustment (and sends the > packets > back), which fixes the problem nicely, but that's kinda a hack. > > I checked "man interfaces", but didn't see anything too obvious... > > I'm running Woody on this box. > > Thanks! -rt > > -- > Ryan S. Tucker > Network Engineer > ISP Direct, Inc. > 1159 Pittsford-Victor Road, Suite 140 > Pittsford, New York 14534 > +1 585 419-8200 > http://www.netacc.net/ > > > -- > To UNSUBSCRIBE, email to [EMAIL PROTECTED] > with a subject of "unsubscribe". Trouble? Contact > [EMAIL PROTECTED] >
Re: Adjusting MTU
maybe ifconfig could help you, some of the way ? $ ifconfig eth1 mtu 1250 $ man 8 ifconfig im not sure where to put this , to make sure its there at startup (the Debian way). Maybe somebody else can help with that? * Ryan Tucker ([EMAIL PROTECTED]) wrote: > Greetings... > > I'm trying to find the "Debian Way" to adjust the MTU on an interface... > basically, we have a box behind a firewall which is blocking the ICMP > Can't Fragment packets, and we're sending fairly large data packets > through, and, well, the obvious problem occurs. They can put a little > firewall on the LAN which has an MTU adjustment (and sends the packets > back), which fixes the problem nicely, but that's kinda a hack. > > I checked "man interfaces", but didn't see anything too obvious... > > I'm running Woody on this box. > > Thanks! -rt > > -- > Ryan S. Tucker > Network Engineer > ISP Direct, Inc. > 1159 Pittsford-Victor Road, Suite 140 > Pittsford, New York 14534 > +1 585 419-8200 > http://www.netacc.net/
Adjusting MTU
Greetings... I'm trying to find the "Debian Way" to adjust the MTU on an interface... basically, we have a box behind a firewall which is blocking the ICMP Can't Fragment packets, and we're sending fairly large data packets through, and, well, the obvious problem occurs. They can put a little firewall on the LAN which has an MTU adjustment (and sends the packets back), which fixes the problem nicely, but that's kinda a hack. I checked "man interfaces", but didn't see anything too obvious... I'm running Woody on this box. Thanks! -rt -- Ryan S. Tucker Network Engineer ISP Direct, Inc. 1159 Pittsford-Victor Road, Suite 140 Pittsford, New York 14534 +1 585 419-8200 http://www.netacc.net/
Re: Adjusting MTU
maybe not the best way, but I have in my /etc/network/interfaces file It puts it all in a place that is easy to find and use auto eth3 iface eth3 inet static address 192.168.1.1 netmask 255.255.255.0 network 192.168.1.0 broadcast 192.168.2.255 up route add -net 192.168.100.0 netmask 255.255.255.0 gw 192.168.1.254 up ifconfig eth3 mtu 500 It may be better to do a pre-up though so it gets done before the interface is brought up auto eth3 iface eth3 inet static address 192.168.1.1 pre-up ifconfig eth3 mtu 500 Chris --- Ryan Tucker <[EMAIL PROTECTED]> wrote: > Greetings... > > I'm trying to find the "Debian Way" to adjust the MTU on an > interface... > basically, we have a box behind a firewall which is blocking the ICMP > > Can't Fragment packets, and we're sending fairly large data packets > through, and, well, the obvious problem occurs. They can put a > little > firewall on the LAN which has an MTU adjustment (and sends the > packets > back), which fixes the problem nicely, but that's kinda a hack. > > I checked "man interfaces", but didn't see anything too obvious... > > I'm running Woody on this box. > > Thanks! -rt > > -- > Ryan S. Tucker > Network Engineer > ISP Direct, Inc. > 1159 Pittsford-Victor Road, Suite 140 > Pittsford, New York 14534 > +1 585 419-8200 > http://www.netacc.net/ > > > -- > To UNSUBSCRIBE, email to [EMAIL PROTECTED] > with a subject of "unsubscribe". Trouble? Contact > [EMAIL PROTECTED] > -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Re: Adjusting MTU
maybe ifconfig could help you, some of the way ? $ ifconfig eth1 mtu 1250 $ man 8 ifconfig im not sure where to put this , to make sure its there at startup (the Debian way). Maybe somebody else can help with that? * Ryan Tucker ([EMAIL PROTECTED]) wrote: > Greetings... > > I'm trying to find the "Debian Way" to adjust the MTU on an interface... > basically, we have a box behind a firewall which is blocking the ICMP > Can't Fragment packets, and we're sending fairly large data packets > through, and, well, the obvious problem occurs. They can put a little > firewall on the LAN which has an MTU adjustment (and sends the packets > back), which fixes the problem nicely, but that's kinda a hack. > > I checked "man interfaces", but didn't see anything too obvious... > > I'm running Woody on this box. > > Thanks! -rt > > -- > Ryan S. Tucker > Network Engineer > ISP Direct, Inc. > 1159 Pittsford-Victor Road, Suite 140 > Pittsford, New York 14534 > +1 585 419-8200 > http://www.netacc.net/ -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
Adjusting MTU
Greetings... I'm trying to find the "Debian Way" to adjust the MTU on an interface... basically, we have a box behind a firewall which is blocking the ICMP Can't Fragment packets, and we're sending fairly large data packets through, and, well, the obvious problem occurs. They can put a little firewall on the LAN which has an MTU adjustment (and sends the packets back), which fixes the problem nicely, but that's kinda a hack. I checked "man interfaces", but didn't see anything too obvious... I'm running Woody on this box. Thanks! -rt -- Ryan S. Tucker Network Engineer ISP Direct, Inc. 1159 Pittsford-Victor Road, Suite 140 Pittsford, New York 14534 +1 585 419-8200 http://www.netacc.net/ -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
