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network_stuff:linux

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network_stuff:linux [2024/10/06 17:14] – jotasandokunetwork_stuff:linux [2024/10/06 17:17] (current) – jotasandoku
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   * DHCPRequest: src:0.0.0.0 ; dst: broadcast << PACKET HAS BOOTP FLAG UNSET   * DHCPRequest: src:0.0.0.0 ; dst: broadcast << PACKET HAS BOOTP FLAG UNSET
   * DHCPAck: : src: server IP ; dst: client-mac + tentative IP Address   * DHCPAck: : src: server IP ; dst: client-mac + tentative IP Address
 +===== DHCP Options =====
  
-===== Circuit ID & Remote ID Examples =====+  * **Default gateway (3):** Specifies the default gateway. Not used in DHCPv6. 
 +  * **Domain names (15):** Provides domain names for DNS resolution. 
 +  * **Vendor-Specific Info (43):** Used in Cisco PnP to point to the PnP server. 
 +  * **Subnet Mask (1):** Defines the subnet mask for the network. 
 +  * **IP lease time (51):** Specifies the duration of the IP address lease. 
 +  * **Renewal time (58):** Time when the client should renew the lease with the DHCP server. 
 +  * **Rebinding time (59):** Time when the client should attempt to rebind if the lease cannot be renewed. 
 +  * **Bootfile name (67):** Location of the boot file or script, often used in ZTP (Zero Touch Provisioning). 
 +  * **Relay Agent Info (82):** Adds metadata (e.g., VLAN, switch ID) to DHCP requests. Enabled by default with DHCP snooping for security. Can cause issues with non-Cisco DHCP servers.  
 +    * **Suboptions:** 
 +      * **Circuit ID:** Identifies the switch port (e.g., VLAN 10, port 2). 
 +      * **Remote ID:** Identifies the relay agent (e.g., Switch-1).
  
-DHCP Option 82 adds two key sub-options: **Circuit ID** and **Remote ID**.+===== Additional Relevant Options =====
  
-==== Circuit ID ==== +  * **DNS Servers (6):** Provides the IP addresses of DNS servers. 
-Identifies the specific port or circuit where the request originated. +  * **Router (3):** Specifies the router’s IP address for client devices. 
- +  * **TFTP Server (66):** Location of the TFTP server, often used for network device configurations. 
-  * **Example 1 (Switch Port)**:  +  * **NTP Servers (42):** Specifies the Network Time Protocol (NTP) server to synchronize time.
-    - ''Circuit ID: vlan10, port2'' +
-    - Indicates the request came from VLAN 10, port 2. +
- +
-  * **Example 2 (Service Provider)**:  +
-    - ''Circuit ID: ISP-POP3-Router2, Ethernet0/1'' +
-    - Identifies the point of presence (POP) and the router interface where the request was received. +
- +
-==== Remote ID ==== +
-Identifies the switch or device that relayed the DHCP request. +
- +
-  * **Example 1 (Switch ID)**:  +
-    - ''Remote ID: Switch-1'' +
-    - Indicates the request was relayed by Switch-1. +
- +
-  * **Example 2 (MAC Address)**:  +
-    - ''Remote ID: 00:1A:2B:3C:4D:5E'' +
-    - Uses the MAC address of the relay agent. +
- +
-  * **Example 3 (Location-Based)**:  +
-    - ''Remote ID: DC1-Switch-2'' +
-    - Specifies the relay was Switch-2 in Data Center 1. +
- +
-==== Combined Example ==== +
-  * ''Option 82: Circuit ID: vlan20, port3 | Remote ID: Switch-3'' +
-  - The request came from VLAN 20, port 3, and was relayed by Switch-3.+
  
  
network_stuff/linux.1728234889.txt.gz · Last modified: by jotasandoku

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