Begin forwarded message:
> Date: Tue, 15 Nov 2005 03:01:49 -0800 > From: [EMAIL PROTECTED] > To: [EMAIL PROTECTED] > Subject: [Bug 5610] New: IP MTU Path Discovery now working properly > > > http://bugzilla.kernel.org/show_bug.cgi?id=5610 > > Summary: IP MTU Path Discovery now working properly > Kernel Version: 2.6.12 > Status: NEW > Severity: normal > Owner: [EMAIL PROTECTED] > Submitter: [EMAIL PROTECTED] > > > Most recent kernel where this bug did not occur: > Distribution: Ubuntu > Hardware Environment: Laptop Acer Aspire 3500 > Software Environment: > Problem Description: Performing ftp upload on a network that has an > MTU of 1400 along the way. Local interface MTU is set to 1500. Laptop > receives from the network ICMP Destination Unreachable (Fragmentation > Needed), MTU of next hop 1400, but i see no reduction on the IP > packet size sent by the Laptop. > > Because the IP MTU Path Discovery mechanism is enabled, all the > outoing packets have the DF flag set, causing this TCP session to > stall. ======================== The trace (see bugzilla attachment) shows 161.30.105.72.ftp-data > 192.168.128.101.32792: . ack 1 win 64000 192.168.128.101.32792 > 161.30.105.72.ftp-data: . 1:1381(1380) ack 1 win 5840 192.168.128.101.32792 > 161.30.105.72.ftp-data: . 1381:2761(1380) ack 1 win 5840 161.30.14.93 > 192.168.128.101: icmp 36: 161.30.105.72 unreachable - need to frag (mtu 1400) 161.30.14.93 > 192.168.128.101: icmp 36: 161.30.105.72 unreachable - need to frag (mtu 1400) 192.168.128.101.32792 > 161.30.105.72.ftp-data: . 1:1381(1380) ack 1 win 5840 161.30.14.93 > 192.168.128.101: icmp 36: 161.30.105.72 unreachable - need to frag (mtu 1400) 192.168.128.101.32792 > 161.30.105.72.ftp-data: . 1:1381(1380) ack 1 win 5840 161.30.14.93 > 192.168.128.101: icmp 36: 161.30.105.72 unreachable - need to frag (mtu 1400) 192.168.128.101.32792 > 161.30.105.72.ftp-data: . 1:1381(1380) ack 1 win 5840 161.30.14.93 > 192.168.128.101: icmp 36: 161.30.105.72 unreachable - need to frag (mtu 1400) - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
