IP Reservation / IP-Mac Binding or Both ?

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IP Reservation / IP-Mac Binding or Both ?

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IP Reservation / IP-Mac Binding or Both ?
IP Reservation / IP-Mac Binding or Both ?
2020-07-07 05:24:59 - last edited 2020-07-09 05:41:48
Model: Archer C5400X  
Hardware Version: V1
Firmware Version: 1.1.2 Build 20191223 rel.73956(5553)

This is my first TP link router and I'm noticing there's features in it I've never seen before such as IP-Mac Binding.. I know what IP Reservation is for as I use it, And I understand from what I've read how IP-Mac binding is suppose to help protect devices on a network. But what I'm not sure of, Are they supposed to be used independently using one or the other ? Or can they both be used at the same time ? This is my first TPLink router and I'm noticing features that I've never seen before.... 



Best Regards 

Jim 

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Re:IP Reservation / IP-Mac Binding or Both ? -Solution
2020-07-09 05:40:51 - last edited 2020-07-09 05:41:48

@Jim-69 

 

Hello, 

 

"DHCP address reservation" or "IP Reservation" specifically means that the router will always offer the given address whenever the host asks for one using the DHCP auto-configuration protocol. However, only DHCP offers were made static, but the router's IP-MAC neighbor cache (aka the ARP cache) is still filled in dynamically using ARP. Meaning, if you bypass DHCP and manually configure another host to use the reserved address, it'll work. As soon as the "IP-old MAC" cache entry expires, the router sends a new ARP query, learns the new MAC address, adds "IP-new MAC" to the ARP cache, and packets go to the 'new' host.

 

"IP-MAC binding" or "ARP Binding" won't necessarily affect DHCP, but it does add a fixed IP-MAC entry to the router's neighbor cache. If another host tries to use the same IP address, the router won't know that. It will trust the fixed IP-MAC binding, and will always send packets to the "bound" MAC address, even if the host is actually offline.

 

So far, IP-MAC binding primarily sounds like a security feature, it partially avoids "ARP spoofing" attacks, and works even if DHCP is turned off entirely.

 

Hope this helps.

 

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Re:IP Reservation / IP-Mac Binding or Both ? -Solution
2020-07-09 05:40:51 - last edited 2020-07-09 05:41:48

@Jim-69 

 

Hello, 

 

"DHCP address reservation" or "IP Reservation" specifically means that the router will always offer the given address whenever the host asks for one using the DHCP auto-configuration protocol. However, only DHCP offers were made static, but the router's IP-MAC neighbor cache (aka the ARP cache) is still filled in dynamically using ARP. Meaning, if you bypass DHCP and manually configure another host to use the reserved address, it'll work. As soon as the "IP-old MAC" cache entry expires, the router sends a new ARP query, learns the new MAC address, adds "IP-new MAC" to the ARP cache, and packets go to the 'new' host.

 

"IP-MAC binding" or "ARP Binding" won't necessarily affect DHCP, but it does add a fixed IP-MAC entry to the router's neighbor cache. If another host tries to use the same IP address, the router won't know that. It will trust the fixed IP-MAC binding, and will always send packets to the "bound" MAC address, even if the host is actually offline.

 

So far, IP-MAC binding primarily sounds like a security feature, it partially avoids "ARP spoofing" attacks, and works even if DHCP is turned off entirely.

 

Hope this helps.

 

Nice to Meet You in Our TP-Link Community. Check Out the Latest Posts: Connect TP-Link Archer BE550 to Germany's DS-Lite (Dual Stack Lite) Internet via WAN Archer GE550 - BE9300 Tri-Band Wi-Fi 7 Gaming Router EasyMesh Is Available When Wi-Fi Routers Work in AP Mode as A Controller. Archer AX55V2 Supports WireGuard VPN, EasyMesh Ethernet Backhaul, IoT Network, Speed Limit,and More If you found a post or response helpful, please click Helpful (arrow pointing upward icon). If you are the author of a topic, remember to mark a helpful reply as the "Recommended Solution" (star icon) so that others can benefit from it.
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