GT-AC5300 - DHCP lease issues

[ddebacker]

I'm trying to set a DHCP static lease for a new PC. That new PC has obtained a dynamic lease before I configured the static one.

I've changed the DHCP config (added the static lease to the correct MAC address of my NIC in the Asus config webpgage.

New static lease is visible in the Asus LAN - DHCP server settings page but even though I did an IPCONFIG /RELEASE on the client, rebooted it twice it still gets the old (dynamically assigned) IP and NOT the one from the static entry.

Is there something I'm missing? I'm running the latest Asus official firmware on the router (3.0.0.4.386_51529).

Thanks!

 

[ColinTaylor]

Do you see the DHCPDISCOVER/OFFER/REQUEST/ACK messages for the PC in System Log - General Log?

It might be worth rebooting the router also if you haven't already tried that.

 

[bbunge]

First off, static IP addresses are assigned at the client. Manually Assigned IP Addresses are assigned by the DHCP Server which, in your case, is the router. The Manually assigned address may not be assigned until the DHCP Lease Time has expired. Another way is to reboot the router.
If you have a need for the client to have an IP address that does not change (printer, server, NAS and etc.) it is best to set the static IP address at the client and leave a pool of addresses free for your static clients. For example, IP Pool Starting address at 192.168.50.50 and you will have 48 addresses you can use for static. The benefit is if you have to reset the router you do not have to do a bunch of manually assigned addresses.

 

[ddebacker]

First off, static IP addresses are assigned at the client. Manually Assigned IP Addresses are assigned by the DHCP Server which, in your case, is the router. The Manually assigned address may not be assigned until the DHCP Lease Time has expired. Another way is to reboot the router.
If you have a need for the client to have an IP address that does not change (printer, server, NAS and etc.) it is best to set the static IP address at the client and leave a pool of addresses free for your static clients. For example, IP Pool Starting address at 192.168.50.50 and you will have 48 addresses you can use for static. The benefit is if you have to reset the router you do not have to do a bunch of manually assigned addresses.

I respectfully agree and disagree. I like centralized management and my PC (laptop) moves from one place to the other. When home I like to have a specific IP because of port forwarding requirements.
It's then easier for me to set a static lease (sorry for the lack of better words, that's how it's called in servers environments) so that when my laptop DHCP client send a DHCP requests and my router replies to it, it send back the same IP even even though the lease expired.

I believe I'll have to wait for my lease to expire before I get the static IP that I assigned on my to my MAC (in the DHCP service properties and yes it's called manual assignments, I just call that static lease which is a shortcut in my mind) to change.

 

[ColinTaylor]

I believe I'll have to wait for my lease to expire before I get the static IP that I assigned on my to my MAC (in the DHCP service properties and yes it's called manual assignments, I just call that static lease which is a shortcut in my mind) to change.

You should not need to wait for the lease to expire. Did you try rebooting the router like I suggested? What about the syslog messages?

 

[ddebacker]

You should not need to wait for the lease to expire. Did you try rebooting the router like I suggested? What about the syslog messages?

15:10:58 dnsmasq-dhcp[26022]: not giving name LAPTOP to the DHCP lease of 192.168.50.13 because the name exists in /etc/hosts with address 192.168.50.10

 

[sfx2000]

I believe I'll have to wait for my lease to expire before I get the static IP that I assigned on my to my MAC (in the DHCP service properties and yes it's called manual assignments, I just call that static lease which is a shortcut in my mind) to change.

The DHCP client should start requesting updates at half period of the DHCP lease time... this is per IETF, and the client should first request the refresh based on the current IP it's assigned, but the server can always re-assign the IP based on current status...

If one is making major changes to the DHCP reservations, I would suggest a restart of the device, as dnsmasq may need to have the config reloaded...

 

[cwerdna]

Not that this helps but GT-AC5300 has hit EOL per https://www.asus.com/event/network/eol-product/.

 

[ddebacker]

I've finally solved my issue by rebooting the router. I couldn't do it anytime I wanted since both me and my wife are working from home and needed the connectivity to stay up.

Thanks to all of you who helped!