Unsupported/Insecure Networks

The Computer Systems Lab has designated several networks as unsupported/Insecure, for computers that can not be on our regular production networks.

What Are The Unsup Networks?

The Computer Systems Lab has designated the following network subnets as unsupported, for computers that can not be on our production networks. This includes computers running insecure operating systems and operating systems not supported by the Systems Lab, and computers not managed by the Systems Lab:

• 128.105.102.0 (100baseT)

The unsupported networks are restricted such that unsup net hosts can only communicate with hosts on the CSL production networks (128.105.0.0), and can not send electronic mail.

How can I test connectivity on the unsup network?

IP addresses are assigned by the CSL for each machine. Do not use any additonal IP addresses without the consent of the CSL. Although ICMP pings are normally filtered, the host ping.cs.wisc.edu (currently 128.105.252.4) should be reachable as a network connectivity check.

What network restrictions are placed on the Unsup network?

We place network restrictions on the unsupported networks as a security precaution for both the rest of the Computer Science Department and to prevent an unsupported host from causing harm to external hosts. Additional ports are sometimes rapidly blocked in the event of widescale worm activity. Also hosts that it is believed have been infected or are causing malicious activity will be disconnected from the network.

blocked ports:

• TCP 25 SMTP
• UDP 69 TFTP
• Microsoft SMB
  • TCP 135 RPC
  • UDP 137 NetBIOS Name Resolution
  • UDP 138 NetBIOS Datagram Service
  • TCP 139 NetBIOS Session Service
  • TCP 445 SMB over TCP/IP
  • TCP 593 RPC over HTTP
• UDP 514 SYSLOG
• TCP 515 LPD
• TCP 587 Submission
• TCP 4444 Blaster Worm
• ICMP Ping
• External CS Access

How Do I Use The Web/FTP On An Unsupported Network?

If you're on the unsup net, or otherwise want to use a caching web proxy, configure your WWW and anonymous FTP proxies to squid.cs.wisc.edu port 3128.

What Is The Network Configuration For The Unsup Networks?

The unsup networks are configured as follows:

Network	128.105.102.0
Netmask	255.255.255.0
Broadcast Address	128.105.102.255
Default Gateway	128.105.102.246
DNS Servers	128.105.252.100

Troubleshooting

• Are the network card indicator lights on? If they are not lit at all, check:
  • that the network cord is plugged securely into the computer and into the wall
  • that the mac address in our records matches the mac address of the network card
• Are you using the correct network settings?
  • check your network settings using ifconfig in linux/mac or ipconfig in windows to check the ip, netmask, and gateway
• Can you ping ping.cs.wisc.edu?
  • if you can ping 128.105.252.4 (ping.cs.wisc.edu's ip) but no the hostname ping.cs.wisc.edu, you may have set your dns server incorrectly.