This chapter contains a complete example of access control list (ACL) configuration.

An Access Control List is a list of Access Control Entries (ACE). Each ACE in ACL specifies the access rights allowed or denied.

Each packet that arrives at the device is compared to each ACE in each ACL in the order they are defined. The device continues to look until it has a match. If no match is found and the device reaches the end of the list, the packet is denied. For this reason, place the most frequently occurring specifications at the top of the list.

The device stops checking the specifications after a match occurs.

Use the commands below to verify the match count. When inbound IP packets reach interface xe10 with source address 1.1.1.1, then the match count for access rule 10 increases equal to the number of packets sent.

When inbound IP packets reach interface xe10 with a source address 1.1.1.2, then the match count for access rule 20 increases equal to the number of packets sent.

Use the commands below to verify the match count. When inbound IP packets reach interface xe10 with source address 1.1.1.X, destination address 2.2.2.X, DSCP value af11, and are fragmented, then the count for access rule 10 increases equal to the number of packets sent.

When inbound IP packets reach interface xe10 with source address as 1.1.1.X, destination address 2.2.2.X, and precedence value flash, then the count for access rule 20 increases equal to the number of packets sent.

You can change the sequence numbers of rules in an access list.

Before re-sequencing:

After re-sequencing the access list, starting with sequence number 100 and incrementing by 200

After re-sequencing specific access rule 100 with sequence number 1000

Use the commands below to verify the match count. When inbound IPv6 packets reach interface xe10 with IPv4, then count for access rule 11 increases equal to the number of packets sent.

For all other IPv6 packets, access rule 100 is invoked and the match counts increase equal to the number of packets sent.

 

Use the commands below to verify the running configurations.

Use the commands below to verify the match count.

 

Use the commands below to verify the running configurations.

!

Use the commands below to verify the match count.

Use the commands below to verify the match count. When inbound packets reach interface xe10 with the specific source and destination MAC with the VLAN as 2, then the count for access rule 22 increases equal to the number of packets sent.

For all other packets, default rule is invoked and the match counts increases equal to the number of packets sent.

Management Port ACL can be used to provide basic level of security for accessing the management network. ACLs can also be used to decide which types of management traffic to be forwarded or blocked at the management port.

When configuring access list on a router or a switch, each access list needs to be identified by a unique name or a number. Each access list entry can have permit or deny actions. Each entry will be associated with a sequence number in the range of <1-268435453>. Lower the sequence number, higher the priority.

User should be able to configure the system to allow certain IP address for a protocol and don’t allow any other IP address matching for that protocol.

Use the commands below to verify the match count. When a TCP connection for Destination Port SSH reach interface eth0 with source address 10.12.45.57, then the match count for access rule 10 increases equal to the number of packets sent.

When a TCP connection for Destination Port Telnet reach interface eth0 with source address 10.12.45.58, then the match count for access rule 20 increases equal to the number of packets sent.

When a UDP packet for Destination Port SNMP reach interface eth0 with any source address, then the match count for access rule 30 increases equal to the number of packets sent. Prior to this SNMP should be configured on Device (10.12.29.49).

When a UDP packet for Destination Port NTP reach interface eth0 with any source address, then the match count for access rule 40 increases equal to the number of packets sent. Prior to this NTP should be configured on Device (10.12.29.49).

When a TCP connection request for Destination Port SSH reach interface eth0 with source address 10.12.45.58, this should deny the connection and the match count for access rule 70 increases equal to the number of packets sent.

When a TCP connection request for Destination Port Telnet reach interface eth0 with source address 10.12.45.57, this should deny the connection and the match count for access rule 80 increases equal to the number of packets sent.

To enable SNMPTRAPS, apply the ACL outbound to the Management interface.

When a UDP packet for Destination Port SNMPTrap sends out of interface eth0 with any Destination address, then the match count for access rule 50 increases equal to the number of packets received. Prior to this SNMPTrap should be configured on Device (10.12.29.49) to listen to port 162.

When an ACL is applied on interface eth0 outbound and inbound together, then we must configure an ACL to establish a TCP connection between source 10.12.29.49 with source Port SSH to destination address 10.12.45.57. When a TCP connection is established on port SSH, then the match count for access rule 10 and 60 increases equal to the number of packets sent and received.

ARP ACL can be used to permit or deny the ARP packets, based on the ARP request or response option configured.

Use the commands below to assign IP address on IXIA and ping from IXIA.

The loopback interface ACL feature provides basic security for management applications accessible through In-band interfaces.

When a Telnet/SSH/NetConf connection is established in the OcNOS, it associates the connection with a virtual terminal (VTY) line. The ACL over VTY feature provides security for management features associated with VTY.

Users can create Standard and Extended ACL rules and attach them to a virtual teletype (VTY) command line interface. These ACL rules are applied on both Management and Default virtual routing forwarding (VRFs).

OcNOS supports both IPv4 and IPv6 access lists for VTY lines, providing flexibility for network configurations.

Applying a standard ACL rule on a VTY line permits or denies only management access protocols such as SSH, Telnet, and SSH-Netconf protocols (port numbers 22,23,830)).

Extended ACL rules are applied as configured by the user, and it is not limited to management protocols only, unlike Standard ACLs.

When a user configures a rule with 'deny any any any' and attaches it to the VTY, it effectively blocks only the Telnet, SSH, and NetConf protocols on the control plane

For example, when a user configures a rule as below and attach them to VTY, If the deny ACL rule includes ’any’ value in protocol, only Telnet/SSH/SSH-NetConf protocols are denied.

 

In general, the VTY ACLs are more specific to management protocols. Hence, the Extended ACL “any” rule translation is enhanced to allow management protocols as follows:

 

The time range feature was introduced to be able to add a timing boundary for specified activities. The activity would start, end and repeat at the specific times set by the user. This time-range feature will enable creating "Timed ACLs". This will help service providers to customize the internet data to customers based on time to increase the video traffic during weekends and reduce data traffic, restrict the internet traffic in school or college non-working hours etc.

Applying ACLs to an Integrated Routing and Bridging (IRB) interface or switchport enables control over packet flow, whether ingress or egress the interface. This capability is essential for maintaining security, managing bandwidth, and ensuring effective routing and bridging.

In this topology, PE1 and PE2 routers have IRB interfaces configured. The IRB interfaces bridge VLAN traffic and route between VLANs, enabling communication between Layer 2 and Layer 3.

ACLs are applied on the IRB interfaces to filter traffic, ensuring only authorized traffic passes through. The P1 router acts as a transit router, forwarding traffic between PE1 and PE2. The P1 router provides core functionality but does not handle IRB interfaces directly.

This configuration ensures that while traffic flows across the network, ACL policies can be enforced at both PE1 and PE2 over the IRB interfaces, securing communication between VLANs and controlling access between external networks.

Perform the following steps to enable EVPN MPLS on an IRB interface while applying ACLs to control ingress or egress traffic:

Applying ACLs to an Integrated Routing and Bridging (IRB) interface or switchport enables control over packet flow, whether ingress or egress the interface. This capability is essential for maintaining security, managing bandwidth, and ensuring effective routing and bridging.

In this topology, PE1 and PE2 routers have IRB interfaces configured. The IRB interfaces bridge VLAN traffic and route between VLANs, enabling communication between Layer 2 and Layer 3.

ACLs are applied on the IRB interfaces to filter traffic, ensuring only authorized traffic passes through. The P1 router acts as a transit router, forwarding traffic between PE1 and PE2. The P1 router provides core functionality but does not handle IRB interfaces directly.

This configuration ensures that while traffic flows across the network, ACL policies can be enforced at both PE1 and PE2 over the IRB interfaces, securing communication between VLANs and controlling access between external networks.