What is the purpose of DHCP option 82?

Option 82 is called the relay agent information option and is inserted by the DHCP relay agent when forwarding client-originated DHCP packets to a DHCP server. Servers recognizing the relay agent information option may use the information to implement IP address or other parameter assignment policies.

What is Option 82 in DHCP snooping?

When the DHCP snooping option-82 feature is enabled on the switch, a subscriber device is identified by the switch port through which it connects to the network (in addition to its MAC address). Multiple hosts on the subscriber LAN can be connected to the same port on the access switch and are uniquely identified.

How do you protect against rogue DHCP server attacks?

What about preventing rogue DHCP servers?

1. Look for IP address conflicts.
2. Keep a properly documented network.
3. Use Active Directory to authorize DHCP servers.
4. Use DHCP snooping and trusted ports on your switches.

What is Option 82 Cisco?

Option 82 serves as refinement to the request, allowing the DHCP server to select a “sub-range” in the pool. (Notice that by default Cisco IOS devices reject packets with zero “giaddr” and by default Cisco Catalyst switches use “giaddr” of zero when configured for DHCP snooping!)

What is option 81 DHCP?

DHCP option 81: Client Fully Qualified Domain Name – this option allows to perform automatic update of the DNS records associated to the client, mainly the A and PTR. In the option we can specify whether the client or the server will update the records and the FQDN associated to the client.

What does DHCP snooping protect against?

What does DHCP Snooping protect against? Rogue DHCP Server Attack. DHCP snooping is designed to guard against rogue DHCP attacks. The switch can be configured to transmit DHCP responses only when they come from the DHCP server’s port.

What does DHCP snooping protect against quizlet?

What does DHCP Snooping protect against? Rogue DHCP server attack. Only $35.99/year. What does Dynamic ARP Inspection protect against? ARP poisoning attacks.

What is a rogue DHCP server and how is it a threat to network security?

A rogue DHCP server is a DHCP server set up on a network by an attacker, or by an unaware user, and is not under the control of network administrators. An accidental rogue device is commonly a modem with DHCP capabilities which a user has attached to the network unaware of the consequences of doing so.

What are DHCP options Infoblox?

DHCP options provide specific configuration and service information to DHCP clients. These options appear as variable-length fields at the end of the DHCP messages that DHCP servers and clients exchange.

What is option 82 DHCP server?

An Option 82 DHCP server can use a relay agent’s identity and client source port information to administer IP addressing policies based on client and relay agent location within the network, regardless of whether the relay agent is the client’s primary relay agent or a secondary agent.

What is DHCP relay agent information option 82?

Option 82 is called the relay agent information option and is inserted by the DHCP relay agent when forwarding client-originated DHCP packets to a DHCP server. Servers recognizing the relay agent information option may use the information to implement IP address or other parameter assignment policies.

What is option 82 used for?

Option 82 is supposed to be used in distributed DHCP server/relay environment, where relays insert additional information to identify the client’s point of attachment.

What is option 82 on VLAN 1?

When a client on Vlan 1 sends a DHCP request, the giaddr will be of 192.168.1.1 but with the addition of Option 82, the DHCP server can differenciate if the client will belong to 192.168.2.0 or 192.168.1.0 subnet.