Transcript for ResNet - University of Michigan

University of Michigan
Residence Halls Networking
In-Room Student Registration System
http://www.umich.edu/~insite
Overview
• 3-tier system (Web/CGI, Oracle Daemon, Java
Client)
• DHCP-based
• Automated - users provide minimal data
• Secure - interface-to-daemon communications are
encrypted
Communications
• Campus routers configured to forward DHCP
requests to single server
• DHCP server issues 10.x.x.x addresses, based on
network of request origin
• User connects to internal SSL-protected web page
• CGI obtains uniqname, MAC, network origin and
sends information (protected by Kerberos) to the
Oracle daemon
Communications (cont)
• Oracle daemon matches uniqname to prestuffed
student housing data
• Database maintains linkage between user/location
data and MAC/IP address
• Cron job reads Oracle information and generates a
new DHCP configuration file
• ISC DHCPD server restarted every five min
Registration Diagram
Diagram Guide
1.
2.
Client requests IP from DHCP server; server responds with a 10.x.x.x address
Client contacts internal, SSL-protected webpage; CGI uses kerberos to authenticate
and verify the username and password
The CGI sends uniqname, IP address, and OS to the SQL daemon;
3.
•
•
•
Sqld does an ARP lookup on the router to determine the MAC address
Sqld queries the Group Server to determine if user is allowed to access this specific network
Sqld attempts to associate username with prestuffed user location data; if this is not
successful, it attempts to fill this data by doing and LDAP query to X.500
4.
If the registration is successful, a new entry is added to the DHCP configuration file,
and the client machine is assigned a real, routed IP address which replaces the
unrouted 10.x.x.x address.
•
The Java client is an administration tool that allows network administrators to use a
GUI to configure and partitions subnets, and to make modifications to student data
and IP assignments.
Deployment Results
Drawbacks
• Users can bypass DHCP and assign themselves a
static IP
• DHCP server must be restarted for updates to take
place
• Users must go to a specific URL to complete the
registration
• Users can not have network access on another
network without administrative intervention
Advantages
• Efficient use of IP space
• Students are not required to know the MAC
address of their NIC
• Contact/location info is gathered from reliable
source rather than having students or consultants
enter the data
• Requires very little administration time beyond
initial configuration of networks
Future Directions
• Improved access control through use of V-LAN
configurable switches
• More feedback and options in the CGI, allowing
users to submit changes to their registration
• Continued development of the java administration
tool
• Modularization of code
• Allow machines to “roam” on allowed networks