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dhcp_reservation [2021/03/28 15:28] – created hogwild | dhcp_reservation [2024/09/12 18:11] (current) – [DHCP Reservation] -condense, formatting hogwild | ||
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- | ====== DHCP Reservation | + | ====== DHCP Reservation ====== |
+ | |||
+ | The DHCP Reservation menu contains settings to configure DHCP Reservations, | ||
- | The Static DHCP/ | ||
===== DHCP Reservation ===== | ===== DHCP Reservation ===== | ||
- | Since Tomato | + | Since FreshTomato |
+ | |||
+ | DHCP Reservation is a simple way to ensure FreshTomato offers certain client devices the same IP address each time they request a lease. Simply enter the MAC address for a client device (which you can find on the Device List), into the **MAC Address** field, enter the **IP Address** (and optionally, **Hostname**) you want to assign to this device into those respective fields and click Save. | ||
+ | |||
+ | FreshTomato will then offer that IP address (and hostname) to the MAC address you specified every time it offers a lease. Thus, in general, the client device will always get that IP address whenever it requests one. That last part, “whenever it requests one” is the key part here. See the explanation of the term Hostname later on this page. | ||
+ | |||
+ | Note that you don't need to check the **Bound to** button to make a DHCP Reservation. **Bound to** is used only used to enable Static ARP binding. | ||
- | DHCP Reservation is a simple way to ensure that Tomato offers certain client devices the same IP address each time they request a lease. Simply enter the MAC address for a client device (which you can find on the Device List), into the **MAC Address** field, enter the **IP Address** (and optionally, **Hostname**) you want to assign to this device into those respective fields and click Save. NOTE that you don't need to check the **Bound to** button. Only check the **Bound to** button if you want to enable Static ARP binding. Tomato then offers that IP address (and hostname) to the MAC address you specified every time it offers a lease. This means that, in general, the client device will always get that IP address //whenever it requests one//. That last part, “whenever it requests one” is the key part here. See the explanation of the term Hostname later on this page. | ||
=== Configuring Static DHCP === | === Configuring Static DHCP === | ||
- | When assigning Static DHCP leases, you should use an IP address within | + | When assigning Static DHCP leases, you should use an IP address within |
- | If you want to assign multiple hostnames to the same IP address (for example, you want the the server 10.0.1.3 to be known as both “galaxy” and “mail”, you must separate them in the hostname field with a space. A space isn't a valid DHCP Hostname character, so you must use a hyphen for a single, multi-word hostname like “My-PC”. If a client device has multiple network interfaces (for example, Ethernet and Wi-Fi) with different MAC addresses, | + | If you want to assign multiple hostnames to the same IP address (for example, you want the the server 10.0.1.3 to be known as both “galaxy” and “mail”, you must separate them in the hostname field with a space. A space isn't a valid DHCP Hostname character, so you must use a hyphen for a single, multi-word hostname like “My-PC”. If a client device has multiple network interfaces (for example, Ethernet and Wi-Fi) with different MAC addresses, |
- | If Tomato | + | If FreshTomato |
- | [[https:// | + | \\ |
+ | |||
+ | {{:: | ||
+ | |||
+ | \\ | ||
=== Security Limitations === | === Security Limitations === | ||
- | As mentioned earlier, Static DHCP offers the mapped IP address (and Hostname) to the MAC address you specified every time it offers a lease. Static DHCP does not prevent a different client from being configured with the same IP address. This is because Static DHCP only offers a static mapping to client devices which request a lease. If another device were to use Static IP, or the router or DHCP were disabled, the other device could take the IP address for itself. Similarly, if the first client for which Static DHCP were then configured for Static IP, it could claim a different IP address than the one in Tomato's Static DHCP mapping. | + | As mentioned earlier, Static DHCP offers the mapped IP address (and Hostname) to the MAC address you specified every time it offers a lease. Static DHCP does not prevent a different client from being configured with the same IP address. This is because Static DHCP only offers a static mapping to client devices which request a lease. If another device were to use Static IP, or the router or DHCP were disabled, the other device could take the IP address for itself. Similarly, if the first client for which Static DHCP were then configured for Static IP, it could claim a different IP address than the one in FreshTomato's Static DHCP mapping. |
+ | |||
+ | Even if everything else were working properly, only DHCP lease //offers// are made static. The router' | ||
+ | |||
+ | In these circumstances, | ||
- | Even if everything else were working properly, only DHCP lease //offers// are made static. The router' | ||
=== Inconsistent Terminology === | === Inconsistent Terminology === | ||
- | Technically, | + | Technically, |
+ | |||
+ | Second, Static DHCP is also given different names by different hardware vendors. To make things more confusing, this feature is called //static DHCP assignment// | ||
+ | |||
+ | ---- | ||
+ | |||
+ | ~~REFNOTES~~ | ||
+ | |||
+ | [(ref_1)] | ||
+ | |||
+ | FreshTomato will use input for 2 MAC addresses per IP/ | ||
+ | |||
+ | [[https:// | ||
- | Second, Static DHCP is also given different names by different hardware vendors. This feature is called //static DHCP assignment// | ||
===== Static ARP ===== | ===== Static ARP ===== | ||
- | ARP is a protocol that clients use to obtain the MAC address of another client, given its IP address. ARP is used so that clients can figure out how to address network packets to another client. If a network client needs to communicate with another client, it broadcasts an ARP request across the network asking for the other client' | + | ARP is a protocol that clients use to obtain the MAC address of another client, given its IP address. ARP is used so that clients can figure out how to address network packets to another client. If a network client needs to communicate with another client, it broadcasts an ARP request across the network asking for the other client' |
=== Reduces Broadcast Traffic === | === Reduces Broadcast Traffic === | ||
- | Since ARP requests are broadcast across the network, they add to network traffic. Having | + | Since ARP requests are broadcast across the network, they add to network traffic. Having |
=== Reduces ARP spoofing === | === Reduces ARP spoofing === | ||
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By default, ARP gets its mapping information from other clients on the network. It works in a peer-to-peer fashion. ARP mappings are assumed to be " | By default, ARP gets its mapping information from other clients on the network. It works in a peer-to-peer fashion. ARP mappings are assumed to be " | ||
- | Here again, Static ARP binding can help. When enabled, Static ARP binding will ignore ARP spoofing attempts. | + | Here again, Static ARP binding can help. When enabled, Static ARP binding will ignore ARP spoofing attempts. |
**MAC Address: **Here you enter the MAC Address you wish to bind. | **MAC Address: **Here you enter the MAC Address you wish to bind. | ||
- | **Bound To: **This checkbox enables Static ARP binding for the IP - MAC address mapping. It adds a Static ARP entry for the mapping in Tomato's ARP table based on data it finds in the Static DHCP table. (Default: Disabled). | + | **Bound To: **This checkbox enables Static ARP binding for the IP - MAC address mapping. It adds a Static ARP entry for the mapping in FreshTomato's ARP table based on data it finds in the Static DHCP table. (Default: Disabled). |
**IP Address:** Here you enter the IP address you wish to be bound to the MAC address you entered. | **IP Address:** Here you enter the IP address you wish to be bound to the MAC address you entered. | ||
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===== IPT ===== | ===== IPT ===== | ||
- | IPT stands for IP Traffic Monitoring. | + | IPT stands for IP Traffic Monitoring. |