Sep232009

Cisco Clean Access + Mac OS X = Headache

At Ferris State University, the network implements a system called Cisco Clean Access (CCA). This is a system designed to keep all Windows-based computers up-to-date, secure, and authorized to use the network. On the Windows-side of things, it works decently. All that is truly required is the installation of Clean Access Manager, Norton Antivirus, and setting up your Windows Update settings to point to FSU's Windows Update Server.

This is totally different if you use a Mac (or Linux, or any other OS). While there is technically a Mac client for CCA, it does not work as well as the Windows-based client. Luckily, there is still a backup plan for other operating systems: CCA will redirect you to a web-based login page, you fill in your user credentials, and bam! you're on the network. Only a few caveats:

  • If you disconnect from the network for any reason (i.e. you're using a laptop and you close the lid) for more than 5 minutes, you will have to re-login
  • Occasionally there are issues with computer identification and DHCP: I have run into issues where I was logged in, closed my laptop for 15 minutes, and was given an "IP in use" error. This has happened on more than one occasion, and not only to me, but a few of my classmates.
  • It's just a hassle to have your web session interrupted by a Java app (and on that point, why is it a Java app? I'm pretty sure a standards-compliant web form would suffice) asking you to login

To get around most of these issues, I came up with a script to automatically login with my iMac. Essentially, it's just a shell/bash script that is executed by launchd (you could use Cron on *NIX) every 5 minutes.

Using the script

I set this up using launchd, which is Apple's recommended task scheduler. To do this, I used Lingon (now discontinued), but you can manually set it up as well:

  1. Copy the login script into /Library/Scripts/Shell/ with the name FSUNetworkLogin.sh (it can be downloaded here: FSU Network Login Script); be sure to change your username and password: `bash #!/bin/bash
    \# STARTING AUTHORIZATION logger -i -s "FSUNETWORKLOGIN: Automatically Logging into FSU Network…"
    
    \# GETTING THE ADDRESS FOR AUTHORIZATION AUTHREDURL=\`curl -s http://www.google.com | grep -o URL=.\*\\\\<\\/head##"\` if \[ "$AUTHREDURL" != "" \]; then logger -i -s "FSUNETWORKLOGIN: AUTHREDURL=$AUTHREDURL" SUBDOMAIN=\`echo $AUTHREDURL | sed -e 's#URL=https://##' -e 's#\\.ferris.\*##' -e 's#https://##'\` logger -i -s "FSUNETWORKLOGIN: SUBDOMAIN=$SUBDOMAIN" CM=\`echo $AUTHREDURL | sed -e 's#https://##' -e 's#\[A-z0-9./\]\*?cm=##' -e 's#&uri=\[A-z0-9./%\]\*##'\` logger -i -s "FSUNETWORKLOGIN: CM=$CM" S3=\`curl -s $AUTHREDURL | grep -o 'value="-\\?\[0-9\]\\+" />' | sed -e 's#value="##' -e 's#" />##'\` logger -i -s "FSUNETWORKLOGIN: S3=$S3"
    
    \# GETTING AUTHORIZATION VARIABLES
    
    \# ACTUAL FORM VALUES USERNAME="username" # CHANGE TO YOUR USERNAME PASSWORD="password" # CHANGE TO YOUR PASSWORD PROVIDER="Authentication Cluster"
    
    \# HIDDEN FORM VALUES GUESTUSERNAMELABEL="Guest ID" GUESTPASSWORDLABEL="Password" PASSWORDLABEL="Password" USERNAMELABEL="Computing ID" REGISTERGUEST="NO" COMPACT="false" PAGEID="-1" INDEX="7" PM="" SESSION=$S3 USERIP=$IP URI="http://www.google.com/" REQFROM="perfigo\_login.jsp" CM=""
    
    FULLSTRING="username=$USERNAME&password=$PASSWORD&provider=$PROVIDER&guestUserNameLabel=$GUESTUSERNAMELABEL&guestPasswordLabel=$GUESTPASSWORDLABEL&passwordLabel=$PASSWORDLABEL&userNameLabel=$USERNAMELABEL&registerGuest=$REGISTERGUEST&compact=$COMPACT&pageid=$PAGEID&index=$INDEX&pm=$PM&session=$SESSION&userip=$USERIP&cm=$CM&uri=$URI&reqFrom=$REQFROM" logger -i -s "FSUNETWORKLOGIN: FULLSTRING=$FULLSTRING"
    
    \# SENDING AUTHORIZATION
    
    STATUS=\`curl --max-time 60 --connect-timeout 30 -A "Mozilla/4.0" -d "$FULLSTRING" https://$SUBDOMAIN.ferris.edu/auth/perfigo\_cm\_validate.jsp\`
    
    logger -i -s "FSUNETWORKLOGIN: Status=$STATUS" else logger -i -s "FSUNETWORKLOGIN: Could not complete; you may already be logged in or the internet connection is not available." fi
    
    \# Maybe this will fix the weird launchd things sleep 10 exit 0
2. Create a new file in _/Library/LaunchDaemons/_ called _edu.ferris.network.automaticlogin.plist_, or whatever you want to call it, and paste this into it (or download the file here: [edu.ferris.network.automaticlogin](http://assets.brandonmartinez.com/brandonmartinez/2009/09/edu.ferris.network.automaticlogin.plist)): ``` xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>Disabled</key> <false/> <key>Label</key> <string>edu.ferris.network.automaticlogin</string> <key>ProgramArguments</key> <array> <string>/Library/Scripts/Shell/FSUNetworkLogin.sh</string> </array> <key>StartInterval</key> <integer>300</integer> </dict> </plist>
  1. Open a terminal and make sure that permission are correct:

    cd /Library/Scripts/Shell/ sudo chmod 755 FSUNetworkLogin.sh

  2. Either logout and log back in, or open terminal and issue this command:

    launchctl load ~/Library/LaunchAgents launchctl list

  3. Done! This should log you in every 5 minutes. On occasion, you may experience the login screen, but for the most part you should hardly ever see it.

How the script works

  1. A connection is attempted to google.com using curl
  2. The result is parsed using grep and sed; it is looking for a piece of information common in the FSU CCA Login screen
  3. If the script finds the relevant information, it precedes to send the standard login form data to the CCA Login server
  4. If the script doesn't find the relevant information, then you are already logged in (most likely); the script is aborted
  5. Done!

When it's most beneficial…

For me, this has worked out great. My home setup is pretty elaborate (for just a college residence):

  • Each college residence has 1 network connection, and as such, 1 IP address (generally, this can be overridden with a router in bridge-mode); for me it's an ethernet drop, for others it's a modem
  • From my drop, I plug it into an Airport Extreme (any router would work, though)
  • Behind my router, I have an iMac, a MacBook, a MacMini, an HP Laptop, and my iPhone
  • My router is setup to give out local network addresses on my side of the network (192.168.x.x)
  • I have my iMac setup as the DMZ (this is where the script is installed)

So all I have to do is use my iMac to run the script every 5 minutes and all other devices on my network can use the Internet without having to login. Another awesome benefit is that I know my iMac will be connected and authenticated to the network, so I can access it from anywhere on campus (i.e. file server).

I hope this can help at least someone out. Good luck! Any suggestions or questions, leave a comment.