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dhcp_reservation [2024/09/12 18:04] – [DHCP Reservation] -Condense, reorder parapgraphs. Separate DHCP Res from Static ARP hogwilddhcp_reservation [2024/09/12 18:11] (current) – [DHCP Reservation] -condense, formatting hogwild
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 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. 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 if you want to enable Static ARP binding.+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.
  
 === Configuring Static DHCP === === Configuring Static DHCP ===
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 If FreshTomato can't find a match for the device's Hostname (first priority) or [[https://en.wikipedia.org/wiki/MAC_address|MAC address]] (second priority), the server may fall back to either Dynamic or Automatic allocation. For an explanation of the term //Hostname//, see later on this page. If FreshTomato can't find a match for the device's Hostname (first priority) or [[https://en.wikipedia.org/wiki/MAC_address|MAC address]] (second priority), the server may fall back to either Dynamic or Automatic allocation. For an explanation of the term //Hostname//, see later on this page.
  
-[[https://wiki.freshtomato.org/lib/exe/detail.php?id=static_dhcp_arp_ipt&media=aead7e2e6a4928421e9a3bd59e3b7568.png|{{:aead7e2e6a4928421e9a3bd59e3b7568.png}}]]+ \\ 
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 +{{::basic-dhcp_reservation-2024.1.png?833}} 
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 + \\
  
 === Security Limitations === === Security Limitations ===
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 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. 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's IP→MAC neighbour cache (aka ARP cache) is still filled in dynamically using ARP broadcasts. That means that unless we add something else, FreshTomato is relying on client devices to be honest about their MAC addresses. The source of ARP mapping information is assumed to be “honest” and accurate, even though that source is often the network clients themselves. In these circumstances, there's not much stopping unathorized or malicious clients from pretending to be a different MAC address (ARP spoofing). ARP spoofing could even include spoofing the router or gateway's MAC address. All this could have serious consequences. This is where Static ARP becomes useful.+Even if everything else were working properly, only DHCP lease //offers// are made static. The router's IP→MAC neighbour cache (aka ARP cache) is still filled in dynamically using ARP broadcasts. Unless we change something, FreshTomato is relying on client devices to be honest about their MAC addresses. The source of ARP mapping information is assumed to be “honest” and accurate, even though that source is often the network clients themselves. 
 + 
 +In these circumstances, there's nothing stopping unauthorized/malicious clients from pretending to be a different MAC address (ARP spoofing). ARP spoofing could even include spoofing the router or gateway's MAC address. All this could have serious consequences. This is where Static ARP becomes useful.
  
 === Inconsistent Terminology === === Inconsistent Terminology ===
  
-Technically, FreshTomato's Static DHCP function is a form of //DHCP Reservation// or //DHCP Manual Allocation//. Confusion sometimes occurs because of imprecise or inconsistent terminology. First, it is sometimes confused with //Static IP//. It is not that. Static IP is the setting of an IP address manually from the client device itself. By contrast, Static DHCP involves configuring an assigned IP address for the client device within (FreshTomato's) DHCP server (for when client devices request a DHCP lease).+Technically, FreshTomato's Static DHCP function is a form of //DHCP Reservation// or //DHCP Manual Allocation//. Sometimes, confusion occurs because of imprecise or inconsistent terminology. First, it is sometimes confused with //Static IP//. It is not that. Static IP is the setting of an IP address manually from the client device itself. By contrast, Static DHCP involves configuring an assigned IP address for the client device within (FreshTomato's) DHCP server (for when client devices request a DHCP lease).
  
 Second, Static DHCP is also given different names by different hardware vendors. To make things more confusing, this feature is called //static DHCP assignment// in DD-WRT, //fixed-address// in the Linux dhcp daemon (dhcpd) documentation, //Address Reservation// by Netgear, //DHCP Reservation// or //Static DHCP// by Cisco and Linksys and //IP address reservation// or //MAC/IP address binding// by other router vendors. Hence, one should be precise here, to reduce confusion. Second, Static DHCP is also given different names by different hardware vendors. To make things more confusing, this feature is called //static DHCP assignment// in DD-WRT, //fixed-address// in the Linux dhcp daemon (dhcpd) documentation, //Address Reservation// by Netgear, //DHCP Reservation// or //Static DHCP// by Cisco and Linksys and //IP address reservation// or //MAC/IP address binding// by other router vendors. Hence, one should be precise here, to reduce confusion.
dhcp_reservation.1726160668.txt.gz · Last modified: 2024/09/12 18:04 by hogwild

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