Avocent Access Router Cyclades-PR2000 - Manual (Page 100)

100 Chapter 12 - Filters and Rules
Cyclades-PR2000
Steps necessary to activate filtering on the exterior router in the example:
1 There are two interfaces with two directions each. Filtering on link 1 requires the creation of two rule lists,
called exterior_in and exterior_out . Create them using the menu CONFIG =>RULES LIST =>IP
=>ADD RULE LIST and the following parameters:
Rule List Type = Filter
Default Scope = Deny
Linked Rule List Name = None
2 Create the rules for each rule list in the order in which they should be evaluated. The order is important
and mis-ordering the rules can cause unexpected results. This is done in the menu CONFIG =>RULES
LIST =>IP =>CONFIGURE RULES. The parameters for rules 0 and 1 in the example are shown in Figure
12.4.
3 Link the rule lists to the respective interface parameters in the menu CONFIG =>INTERFACE
=> <INTERFACE> =>NETWORK PROTOCOL =>INCOMING/ OUTGOING RULE LIST NAME. exterior_in
should be set as the incoming rule list name and exterior_out should be set as the outgoing rule list name.
Exterior_in, rule 0 , allows a remote computer to connect to the bastion host using the TCP protocol on
its SMTP port. Exterior_out, rule 0 , allows the Bastion Server to RESPOND to the connection started
by the remote computer. To send e-mail out, two more rules would be needed. If all the router needs to do is
receive e-mail, the configuration is done. If not, other “holes” must be created in the deny ball.