Red Hat Bugzilla – Bug 129811
kernel 2.6.7-1.494.2.2 / sendmail-8.12.11-4.6 smtp slow
Last modified: 2015-01-04 17:08:45 EST
Description of problem:
When sending emails with attachments the server would be occasionally
very slow. The email client would be tied up trying to send.
Version-Release number of selected component (if applicable):
Running Fedora Core 2 with
- kernel 2.6.7-1.494.2.2
Cyclical. At points it wouldn't happen at all then you'd have a point
were nearly everytime you tried to send an email with an attachment it
would slow to a crawl.
Steps to Reproduce:
1. Attempted to send email with attachment from a windows machine
using a linux machine with the above kernel/sendmail running.
Occasionally email would take a very long time to be sent from the
email client to the linux server
Communication to be quicker
I switched back to kernel 2.6.6-1.435.2.3 and the problem seemed to
Default values of these parameters in kernel 2.6.7:
net.ipv4.tcp_default_win_scale = 7
net.ipv4.tcp_moderate_rcvbuf = 1
These values in kernel 2.6.6 were both zero.
I ran the following and it seemed to fix my problem:
sysctl -w net.ipv4.tcp_default_win_scale=0
sysctl -w net.ipv4.tcp_moderate_rcvbuf=0
mass update for old bugs:
Is this still a problem in the 2.6.9 based kernel update ?
Fedora Core 2 has now reached end of life, and no further updates will be
provided by Red Hat. The Fedora legacy project will be producing further kernel
updates for security problems only.
If this bug has not been fixed in the latest Fedora Core 2 update kernel, please
try to reproduce it under Fedora Core 3, and reopen if necessary, changing the
product version accordingly.