TCP patch for Red Hat 6.2 kernel 2.2.14-12

Josip Loncaric josip at
Thu Jun 8 14:58:45 PDT 2000


my TCP patch is now available for Red Hat 6.2 kernel 2.2.14-12:

The web page explains what
this patch does.

Patches for older Red Hat 6.2 kernels are:

Patches for Linux kernels 2.2.12 and 2.2.13 are:

Please verify the md5 checksum after downloading these files to make
certain they did not get corrupted in trasit.  Here are the correct md5

3fc16704ac99651a18e47b7a3eccc675 *tcp-patch-for-2.2.12
f72305c7800552b2449d8288bc63b975 *tcp-patch-for-2.2.13
4841c4c21a3bc10e5fa5d04cfd6288ac *tcp-patch-for-2.2.14-12
4a2d599a5b07676808fe3c6e1769efea *tcp-patch-for-2.2.14-5.0
4138e1c13fd6c3895e56ac6b97773e40 *tcp-patch-for-2.2.14-6.0.1

To apply the patch, download the patch file to /tmp then do the

(1) create a new kernel source tree from original kernel files,
    e.g. cp -a /usr/src/linux-2.2.14 /usr/src/linux-2.2.14-12tcp

(2) cd /usr/src/linux-2.2.14-12tcp
    patch -p1 </tmp/tcp-patch-for-2.2.14-12

(3) verify that the patch was applied correctly, then replace the link
/usr/src/linux with
    ln -s /usr/src/linux-2.2.14-12tcp /usr/src/linux

(4) configure, build and install the new kernel

(5) update network card driver modules as needed

(6) add the following to your /etc/rc.d/rc.local script:

# Based on Fast Ethernet tests with tulip.c:v0.92 driver,
# the recommended strategy is '3' with faster timeouts
if [ -f /proc/sys/net/ipv4/tcp_delack_strategy ]; then
    echo 3 >/proc/sys/net/ipv4/tcp_delack_strategy
if [ -f /proc/sys/net/ipv4/tcp_faster_timeouts ]; then
    echo 1 >/proc/sys/net/ipv4/tcp_faster_timeouts
# Some generally useful network features
if [ -f /proc/sys/net/core/netdev_max_backlog ]; then
    echo 1000 >/proc/sys/net/core/netdev_max_backlog
if [ -f /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts ]; then
    echo 1 >/proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

(7) Re-check your work, run /sbin/lilo, then reboot with the new kernel

After reboot, files /proc/sys/net/ipv4/tcp_delack_strategy and
/proc/sys/net/ipv4/tcp_faster_timeouts should exist and have the values
you specified in your rc.local script.  All TCP sockets which turn on
the TCP_NODELAY socket option (e.g. MPI sockets) will activate the
patch, while all other connections should remain unaffected.  BTW,
tcp_delack_strategy=10 and tcp_faster_timeouts=0 turn off the patch
completely.  These are the defaults after boot, so the patch will not be
active unless these values are changed.



Dr. Josip Loncaric, Senior Staff Scientist        mailto:josip at
ICASE, Mail Stop 132C           PGP key at
NASA Langley Research Center             mailto:j.loncaric at
Hampton, VA 23681-2199, USA    Tel. +1 757 864-2192  Fax +1 757 864-6134

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