9-2 
z  If no ACL is configured on the VTY user interface, users are not controlled when establishing a 
Telnet connection using this user interface. 
z  If an ACL is configured on the VTY user interface, there will be two possibilities: if the packets for 
establishing a Telnet connection match the ACL rule configured on the VTY user interface, the 
connection will be permitted or denied according to the ACL rule; if not, the connection will be 
denied directly. 
Controlling Telnet Users by ACL 
Controlling Telnet users by ACL is achieved by the following two ways: 
z  inbound: Applies the ACL to the users Telnetting to the local switch through the VTY user 
interface. 
z  outbound: Applies the ACL to the users Telnetting to other devices through the current user 
interface. This keyword is unavailable to Layer 2 ACLs. 
You can configure the following three types of ACLs as needed: 
Table 9-2 ACL categories 
Category  ACL number  Matching criteria 
Basic ACL  2000 to 2999  Source IP address 
Advanced ACL  3000 to 3999 
Source IP address and 
destination IP address 
Layer 2 ACL  4000 to 4999  Source MAC address 
 
 
Source and destination in this manual refer to a Telnet client and a Telnet server respectively. 
z  If the inbound keyword is specified, the Telnet client is the user telnetting to the local switch and 
the Telnet server is the local switch. 
z  If the outbound keyword is specified, the Telnet client is the local switch, and the Telnet server is 
another device to which the user is telnetting. 
 
Follow these steps to control Telnet users by ACL: 
To do…  Use the command…  Remarks 
Enter system view 
system-view 
— 
Create a basic ACL or enter 
basic ACL view 
acl number acl-number 
[ match-order { auto | 
config } ] 
As for the acl number command, the 
config keyword is specified by 
default. 
Define rules for the ACL 
rule [ rule-id ] { deny | 
permit } [ rule-string ] 
Required 
Quit to system view 
quit 
— 
Enter user interface view 
user-interface [ type ] 
first-number [ last-number ] 
—