Additional Remote Networking
Examples
5-16
5.8 Examples
5.8.1 Creating a Chat Script
Figure 5-25 displays a sample chat script. This script will send a series of text strings to the remote host, and
will expect particular strings in return. If an expected string is not received from the remote host, the script
will loop up to four times before the entire script fails.
Figure 5-25:
Creating a Chat Script
5.8.2 Creating a Simple Firewall
Firewalls are used to protect a network or networks from unauthorized access. To set up a firewall, a filter
list is used; packet traffic is compared to the filters in the list to determine whether or not it will be
forwarded. In general, firewalls prevent all packet traffic, with the exception of traffic to a particular service
or services.
In this example, a network policy prevents all IP traffic, permitting only ICMP ping packets and email.
Telnet connections are permitted to only one secure host (192.0.1.4) on the local network. The SCS is
calling site
memphis
.
First, create a filter list for IP traffic. This list is called
mem
.
Figure 5-26:
Creating IP Filter
Finally, the
mem
filter list must be associated with site memphis as an incoming filter list.
Figure 5-27:
Assigning mem Filter List to Site memphis
Note:
For a more complex firewall example, see Creating a Firewall on page 11-30.
5.8.3 Controlling Access During Weekend Hours
Configurable time ranges are based on a Sunday-to-Saturday week. If you want to allow or restrict access
for a time period that spans Saturday and Sunday, you need to use multiple commands.
Local>> DEFINE SITE irvine CHAT TIMEOUT 4 FAIL
Local>> DEFINE SITE irvine CHAT SEND ""
Local>> DEFINE SITE irvine CHAT EXPECT "login:"
Local>> DEFINE SITE irvine CHAT SEND "user"
Local>> DEFINE SITE irvine CHAT EXPECT "word:"
Local>> DEFINE SITE irvine CHAT SEND "password"
Local>> DEFINE FILTER mem CREATE
Local>> DEFINE FILTER mem ALLOW IP ICMP
Local>> DEFINE FILTER mem ALLOW IP TCP DPORT EQ SMTP
Local>> DEFINE FILTER mem ALLOW IP DST 255.255.255.255 192.0.1.4 TCP DPORT EQ TELNET
Local>> DEFINE FILTER mem ADD DENY ANY
Local>> DEFINE SITE memphis FILTER INCOMING mem
Summary of Contents for SCS
Page 14: ...xii ...
Page 171: ...Modem Sharing Examples 10 6 ...
Page 314: ...Command Reference Service Commands 12 110 ...
Page 403: ...Show 802 11 Errors Rightmost Number B 5 00000002 Internal error 00000001 Internal error ...
Page 424: ...Index 13 ...