Posted on in System Administration
The true beauty of Mac OS X is Darwin, the BSD-based UNIX that runs under the hood of every Mac OS X computer. Having UNIX handy is what attracted me to OS X, and I know plenty of other administrator-types that have followed suit. Every UNIX variant has commands that …
Posted on in system_administration
As discussed previously, we're going to enable RFC 1323 Window Scaling and increase the default TCP receive and send windows to 1 MB. By default Windows 2000 and XP do not offer window scaling options, but will accept them if offered by the other side. To make our changes, we'll …
Posted on in system_administration
As we have throughout the
TCP Performance Tuning
series, we're going to make sure RFC 1323 Window Scaling is enabled and increase
our send and receive window size to 1 MB. The ndd command is the Solaris
equivalent of sysctl in FreeBSD/Linux/Mac OS X.
sudo ndd -set /dev …Posted on in system_administration
Because Darwin is BSD-based, it's no surprise that Mac OS X TCP Performance Tuning is very similar to FreeBSD TCP Performance Tuning. It is no longer necessary to enable RFC 1323 TCP Extensions (in fact, the option to do so is gone). Also, we'll set the TCP send and receive …
Posted on in system_administration
If you have been following our
TCP Performance Tuning series, you'll know
that we want to enable RFC 1323 Window Scaling and increase the TCP window size
1 MB. To do this, we'll add the following lines to /etc/sysctl.conf and issue
sudo sysctl -p to apply the changes …
Posted on in System Administration
In TCP window scaling and broken routers posted in July of 2004, LWN.net's corbet points out that certain routers are setting the RFC 1323 window scale to 0. This effectively sets the TCP window size for the transmission to the minimum value and greatly inhibits performance. As corbet notes …
Posted on in System Administration
The original TCP specification included a window size no larger than 64 KB. This limitation was introduced by the 16 bit header that specified window size. To achieve the recommended 1 MB window size, RFC 1323 TCP extensions must be enabled. The rest of this post is a somewhat detailed …
Posted on in system_administration
Note: Stanislav Shalunov wrote an excellent article on TCP over WAN Performance Tuning and Troubleshooting. In this series of articles, I want to summarize his findings and provide tuning suggestions for popular operating systems.
Most operating systems today ship with TCP stacks optimized for either LAN (high speed, low latency …
Posted on in System Administration
Note: Now that Google is hosting email domains for free, it has become an interesting alternative for both new and old domains. As always, I've changed the names to protect those affected.
Transitioning a domain to Google can be an arduous task. Once you have set up the domain with …
Posted on in System Administration
Sam Varshavchik with the Courier Mail Server project announced updates for all their major software packages including courier-imap, courier-authlib, and maildrop, in addition to the Courier MTA. The major fix common to most packages appears to be the plugging of a memory leak which only came into play once a …
