What is Layer 2 port security?

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The main function of Port Security of layer 2 switching is to identify the frame address and filter the packets. When a secure port receives a frame, the source and destination MAC address of the frame compared with the MAC address table.

What is l2 security?

One of the most common security threats in the Layer 2 domain, and one of those least likely to be detected, is the threat targeted at disabling the network or compromising network users with the purpose of gleaning sensitive information such as passwords.

What are Layer 2 ports?

Each Layer 2 Ethernet port can connect to a single workstation or server, or to a hub through which workstations or servers connect to the network. On a typical Ethernet hub, all ports connect to a common backplane within the hub, and the bandwidth of the network is shared by all devices attached to the hub.

What is the Layer 2 attacks?

ARP Poisoning and DHCP snooping are layer-2 attacks, where as IP Snooping, ICMP attack, and DoS attack with fake IPs are layer-3 attacks. IP address spoofing: IP address spoofing is a technique that involves replacing the IP address of an IP packet’s sender with another machine’s IP address.

What is the difference between Layer 2 and layer 3 security?

A Layer 2 switch only works with MAC addresses and doesn’t interact with any higher layer addresses, like an IP. A Layer 3 switch, on the other hand, can also do static routing and dynamic routing, which includes IP and virtual local area network (VLAN) communications.

What does Port Security do?

Port Security helps secure the network by preventing unknown devices from forwarding packets. When a link goes down, all dynamically locked addresses are freed. The port security feature offers the following benefits: You can limit the number of MAC addresses on a given port.

What is Layer 3 security?

The Layer 3 approach to security looks at the entire network as a whole including edge devices (firewalls, routers, web servers, anything with public access), endpoints such as workstations along devices connected to the network including mobile phones to create an effective plan for security management.

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What is L1 L2 L3 in networking?

● Bits arrive on wire → physical layer (L1) ● Packets must be delivered across links and. local networks → datalink layer (L2) ● Packets must be delivered between networks. for global delivery → network layer (L3)

What is the purpose of layer 2 switch?

A layer 2 switch is primarily responsible for transporting data on a physical layer and in performing error checking on each transmitted and received frame. A layer 2 switch requires MAC address of NIC on each network node to transmit data.

Why is Layer 2 considered as the weakest link in securing a network?

Security is only as strong as the weakest link in the system, and Layer 2 is considered to be that weak link. This is because LANs were traditionally under the administrative control of a single organization. We inherently trusted all persons and devices connected to our LAN.

How secure is a VLAN?

VLANS – not good for security

But switches with VLANs are not firewalls. They operate at layer 2 (the Ethernet layer) and don’t understand the “state” of the messages flowing through them. This makes the spoofing of VLAN tags trivial – there is no check to detect if a tag has been adjusted by a hacker.

Is VPN a Layer 2?

Layer 2 VPNs are a type of Virtual Private Network (VPN) that uses MPLS labels to transport data. The communication occurs between routers that are known as Provider Edge routers (PEs), as they sit on the edge of the provider’s network, next to the customer’s network.

Is Ethernet a layer 1 or 2?

Ethernet operates in the lower two layers of the OSI model: the Data Link layer and the Physical layer. Ethernet operates across two layers of the OSI model.

What is Switchport port security?

The switchport security feature offers the ability to configure a switchport so that traffic can be limited to only a specific configured MAC address or list of MAC addresses.

How do I secure a port?

How to Secure Open Ports

  1. Access ports using a secure virtual private network (VPN). If a business needed something like RDP, ITS would use an encrypted VPN connection to access RDP instead of leaving it open to the internet.
  2. Use multi-factor authentication.
  3. Implement network segmentation.
  4. Scan network ports regularly.

What is Layer 4 firewall?

Layer 4 firewalls provide the aforementioned functions, as well as the capacity to monitor current internet connections or allow/refuse traffic based on the condition of those connections (i.e. stateful packet investigation).

Is firewall a Layer 7?

The seventh layer of the OSI model, often known as the application layer, allows for more advanced traffic-filtering rules. Rather than filtering traffic based on IP addresses, layer 7 firewalls can investigate the contents of data packets to determine whether they include malware or other cyber dangers.

Is Ethernet a Layer 2 or 3?

Layer 2 of the OSI model is known as the data link layer. The Layer 2 protocol you’re likely most familiar with is Ethernet. Devices in an Ethernet network are identified by a MAC (media access control) address, which is generally hardcoded to a particular device and doesn’t normally change.

Is DHCP a Layer 2 protocol?

DHCP works on Layer 2 in the OSI model.

Is UDP a Layer 3?

TCP and UDP are both very well-known protocols, and they exist at Layer 4.

What is Layer 2 and Layer 3 switch?

Traditional switching operates at layer 2 of the OSI model, where packets are sent to a specific switch port based on destination MAC addresses. Routing operates at layer 3, where packets are sent to a specific next-hop IP address, based on destination IP address.

What is the difference between layer 2 switch and router?

Layer 2 Switch Vs Router

A switch learns all the MAC addresses of all the hosts connected to it in order to pass traffic between hosts in Layer 2. Routers on the other hand allow us the ability to take different networks and pass traffic to one another in Layer 3.

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What are Layer 2 and layer 3 devices?

The layer 2 and Layer 3 differs mainly in the routing function. A Layer 2 switch works with MAC addresses only and does not care about IP address or any items of higher layers. Layer 3 switch, or multilayer switch, can do all the job of a layer 2 switch and additional static routing and dynamic routing as well.

Which command will enable port-security?

Use the switchport port-security command to enable port-security. I have configured port-security so only one MAC address is allowed. Once the switch sees another MAC address on the interface it will be in violation and something will happen.

Which layer of the OSI model does port-security use for securing a port?

Network security is only as strong as the weakest link, because a single weak point if exploited successfully would be enough for an intruder. That weak link can be the data link layer or layer 2 of the OSI reference model.

What is the weakest link in many security measures?

That is why 95% of security breaches are blamed on human error, proving people to be the weakest link in cybersecurity.

What are the threats to LAN security?

LAN Security Threats

  • Viruses. Viruses are generally not a “security” threat to the computers on your LAN (although they can cause plenty of problems).
  • Email Attachments.
  • Probes.
  • Trojan Horses.
  • 3/18/00 Worms.
  • The “netlog” worm.

Can malware jump VLANs?

It is possible, but highly unlikely, that a virus could interfere with the switch to “break” the VLAN setup. If the virus causes a CAM table overflow the switch may revert to acting as a hub, and allow traffic to transverse the VLANs.

How do I make my VLAN more secure?

First, avoid putting any hosts on the default VLAN (VLAN 1). Second, be sure that the native VLAN on every trunk port is an unused VLAN ID. Finally, enable explicit tagging of the native VLAN for all trunk ports. Check out the rest of our blog to learn about other considerations for a Virtual Local Area Network.

What layer of OSI is SSL?

Meanwhile, SSL operates at the application layer of the OSI model. It encrypts HTTP traffic instead of directly encrypting IP packets.

What layer is MPLS?

MPLS is considered to operate at OSI layer “2.5”, below the network layer (layer 3) and above the data link layer (layer 2).

Is OpenVPN a Layer 3?

OpenVPN by default operates in layer 3 mode (also called tun or routing mode) where it can take for example TCP and UDP packets and transfer them through the VPN tunnel to a target location.

What is Level 3 VPN?

Layer 3 VPN (L3VPN) is a type of VPN mode that is built and delivered on OSI layer 3 networking technologies. The entire communication from the core VPN infrastructure is forwarded using layer 3 virtual routing and forwarding techniques. Layer 3 VPN is also known as virtual private routed network (VPRN).

What does Layer 2 connection mean?

Layer 2 refers to the data link layer of the network. This is how data moves across the physical links in your network. It’s how switches within your network talk to one another. Installing Layer 2 on your infrastructure gives you high-speed connectivity between devices.

What is the data called at Layer 2?

The data link layer is Layer 2 in the Open Systems Interconnection (OSI) architecture model for a set of telecommunication protocols. Data bits are encoded, decoded and organized in the data link layer, before they are transported as frames between two adjacent nodes on the same LAN or WAN.

What is port security used for?

By using port security, users can limit the number of MAC addresses that can be learned to a port, set static MAC addresses, and set penalties for that port if it is used by an unauthorized user. Users can either use restrict, shut down or protect port-security commands.

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Why port security is important?

Prevents Thieves from Stealing Goods. Since shipping containers cannot be manned at all times, port security is essential for keeping goods safe from thieves. Some areas of ports are inaccessible for human patrol, but other security measures can protect these items from thieves.

How does port security identify a device?

Using Port Security, you can configure each switch port with a unique list of the MAC addresses of devices that are authorized to access the network through that port. This enables individual ports to detect, prevent, and log attempts by unauthorized devices to communicate through the switch.

What is Switchport port security maximum?

The default “switchport port-security maximum” value for the port is “1”.

What ports are vulnerable?

Common vulnerable ports include:

  • FTP (20, 21)
  • SSH (22)
  • Telnet (23)
  • SMTP (25)
  • DNS (53)
  • NetBIOS over TCP (137, 139)
  • SMB (445)
  • HTTP and HTTPS (80, 443, 8080, 8443)

Why is port 80 not secure?

However, Port 80 provides an HTTP connection under TCP protocol. This port provides an unencrypted connection between the web browser and the web servers, which leaves the sensitive user data exposed to cybercriminals and may lead to severe data misuse.

What are security layers?

Layered security is a network security approach that deploys multiple security controls to protect the most vulnerable areas of your technology environment where a breach or cyberattack could occur.

What are the three elements of layered security?

Layered security, as in the previous example, is known as defense in depth. This security is implemented in overlapping layers that provide the three elements needed to secure assets: prevention, detection, and response.

What are the 3 types of firewalls?

According to their structure, there are three types of firewalls – software firewalls, hardware firewalls, or both.

What is l3 l4 firewall?

Layer 3 firewalls (i.e. packet filtering firewalls) filter traffic based solely on source/destination IP, port, and protocol. Layer 4 firewalls do the above, plus add the ability to track active network connections, and allow/deny traffic based on the state of those sessions (i.e. stateful packet inspection).

What layer is router?

Layer 3, the network layer, is most commonly known as the layer where routing takes place. A router’s main job is to get packets from one network to another. Layer 3 protocols and technologies allow for network-to-network communications.

Is Ethernet a Layer 1 or 2?

IEEE specifies in the family of standards called IEEE 802.3 that the Ethernet protocol touches both Layer 1 (physical layer) and Layer 2 (data link layer) on the Open Systems Interconnection (OSI) model. Ethernet defines two units of transmission: packet and frame.

Why is Layer 2 security so important?

Because any user can gain access to any Ethernet port and be a potential hacker, open campus networks cannot guarantee network security. Because the OSI model was built to allow different communications layers to work without knowledge of each other, Layer 2 security is critical.


The DHCP employs a connectionless service model, using the User Datagram Protocol (UDP). It is implemented with two UDP port numbers for its operations which are the same as for the bootstrap protocol (BOOTP).

What is the difference between L2 and L3?

L3 Switches understand both MAC as well as IP Address. L2 Switches do switching based on only MAC Adressing.

What layer is TCP IP?

TCP/IP uses just one layer (application) to define the functionalities of the upper layers, while OSI uses three layers (application, presentation and session). TCP/IP uses one layer (physical) to define the functionalities of the bottom layers, while OSI uses two layers (physical and data link).