Steven Eppler’s Blog

Here at the school district I was running into a problem where if several Mac OS X wireless clients logged into the network at once, everything slowed down to a crawl. After researching the problem, it looked like the user’s Library and Microsoft User Data folders were causing the problem. I tried turning on OS X’s home folder syncronization, but that didn’t work very well, and filled up our older computers fast. The solution I found was to locally cache the user’s Library and Microsoft User Data folder. To do this, create a symbolic link from the user’s networked ‘Library’ folder and point it to a local source. I chose /tmp/UserCache/username/Library. Here is the login script I created to automate the process:

#! /bin/bash

# Create local user caches of important directories
# Written by Steven Eppler 04/04/2006

export PATH=/bin:/usr/bin:/usr/local/bin:/sbin:/usr/sbin

# Set user variable
user="$1"

# This grabs the user's home directory server
input=`dscl localhost read Search/Users/$user NFSHomeDirectory`
nethomedir=${input:18}

# Or you can hardcode it...
# nethomedir="/Network/Servers/ServerName/Volume/$user"

# Check for blank nethomedir - otherwise you will delete
# the root /Library folder!
if [ """$nethomedir""" != "" ]; then

echo $user
echo $nethomedir

# Create local caching directories
mkdir /tmp/UserCache
mkdir /tmp/UserCache/$user
mkdir /tmp/UserCache/$user/Microsoft\ User\ Data
mkdir /tmp/UserCache/$user/Library

# Give everyone rights to them...
chmod -R ugo=rwx /tmp/UserCache

# Create Documents and Desktop folder (sometimes they don't exist)
mkdir $nethomedir/Documents
mkdir $nethomedir/Desktop

# Delete old folders or links
rm -rf $nethomedir/Library
rm -rf $nethomedir/Documents/Microsoft\ User\ Data

# Create new links
ln -s /tmp/UserCache/$user/Library $nethomedir/Library
ln -s /tmp/UserCache/$user/Microsoft\ User\ Data $nethomedir/Documents/Microsoft\ User\ Data

fi

written by eppler

As posted previously, I have been working on porting my WebTester program from ASP to PHP. New features include:

• Ability to randomize questions
• Integrated HTML Editor (no more manual coding)
• ‘Enter’ key selects Next instead of Previous
• Ported from ASP to PHP (so it can be hosted on a Mac/Linux/Windows box, instead of limited to Windows/IIS)
• Generates math equations on the fly, by converting LaTeX math code into a graphic, such as:
• General UI enhancements

To give it a spin, try out the test server. Here are the addresses:

Take a test: http://webtester.epplersoft.com
Administration: http://webtester.epplersoft.com/admin

The username/password combination to use is: demo/demo

This is not the final, so bugs may exist that have already been fixed. To generate math while creating a test, use the following format:

[tex]a^2 + b^2 = c^2[/tex]

The above will generate this image:

To create your own equations, you can try out a program called MathType by Design Science. I will also list other LaTeX generating programs as I find them.

If you have any questions, just leave a comment.

written by eppler

Recently I’ve been working on porting my WebTester project from ASP to PHP. While doing this I have also been adding new features and fixing bugs as I come across them. New items include:

• Ability to randomize questions
• Integrated HTML Editor (no more manual coding)
• ‘Enter’ key selects Next instead of Previous
• Ported from ASP to PHP (so it can be hosted on a Mac/Linux/Windows box, instead of limited to Windows/IIS)
• Each admin user will only see tests created by that user (except for a super-admin)

It should be finished soon and will be used by Delta County Schools.

written by eppler

Here’s some photos from the 2006 International Consumer Electronics Show

CES2006

Click the Album Picture to view

written by eppler

When using tsclient, a remote desktop/terminal services/vnc client, if you connect in full screen mode to a server it can be difficult to disconnect or switch to another application because there is no ‘control bar’ at the top.

To toggle full screen mode, use the key combination Ctrl+Alt+Enter.

written by eppler

Today I was setting up a VPN server and had to figure out what ports and protocols to enable on our Cisco PIX 515E firewall. Here they are:

PPTP:
To allow PPTP tunnel maintenance traffic, open TCP 1723.
To allow PPTP tunneled data to pass through router, open Protocol ID 47.

L2TP over IPSec
To allow Internet Key Exchange (IKE), open UDP 500.
To allow IPSec Network Address Translation (NAT-T) open UDP 4500.
To allow L2TP traffic, open UDP 1701.

Here’s the Cisco access list: (gre=Protocol ID 47, pptp=1723, isakmp=500)

access-list OUTSIDE permit gre any host OUTSIDEIP
access-list OUTSIDE permit tcp any host OUTSIDEIP eq pptp
access-list OUTSIDE permit udp any host OUTSIDEIP eq 1701
access-list OUTSIDE permit udp any host OUTSIDEIP eq 4500
access-list OUTSIDE permit udp any host OUTSIDEIP eq isakmp


(edited to update UDP port 5500 to 4500 as noted in the comments)

written by eppler

I’ve been using Advanced Policy Firewall (APF) and Brute Force Detection (BFD) on my dedicated servers for a while now for increased security. I just installed them at work for our Linux-based mail servers. The APF install guide is here, and the BFD install guide is here.

written by eppler

We use a program called SolarWinds to monitor our network usage and statistics. But lately, I’ve been getting “The requested resource is in use” while trying to view our network monitoring and statistics page. Not a very helpful message, thanks Microsoft…

This is on a Windows 2003 Server, so it uses IIS (Internet Information Server) and ASP (Active Server Pages) for its graphing and network overview features.

To fix this error, I just made a backup of the server’s configuration, uninstalled IIS, and then reinstalled. That fixed IIS, but SolarWinds couldn’t connect to the database anymore. I re-ran the configuration wizard that comes with SolarWinds, and everything came back.

I’m glad all of my pages are hosted with Apache on CentOS 4.

written by eppler

I ran into a problem today where a graphite iMac was stuck in target mode. Resetting the PRAM did nothing, doing the normal NetBoot shortcut (holding down ‘N’ at startup) did nothing, so I was stuck – for a moment.

To fix this problem, I booted into Open Firmware (using Command+Option+O+F). Then entering these commands allowed the machine to boot from the network:

setenv boot-device enet:10.0.0.2
mac-boot


Of course, substitute “10.0.0.2″ for your NetBoot server – if you’ve got one. Thanks to Mike Bombich’s Netbooting Across Subnets page for the help.

written by eppler

“SharePoints is an application or a preference pane that makes it easy to add and delete share points like in the old Finder. In Mac OS X, by default, you are limited to sharing only what is in your public folder in your home directory. This program makes it easy to share any folder.
In addition SharePoints also brings back users and groups management to Mac OS X as well as easy configuration of AppleFileServer (AFS) and Samba (SMB) Server properties.”

Download SharePoints

written by eppler