Does merlin reset router when assigning DHCP manual IP by MAC?

[Qwinn]

I'm on an AXE16000 router. Mostly I've been fine with the stock firmware, but there is one thing that would definitely move me to switch to merlin:

My ISP only provides me with a dynamic IP address. Whenever I modify the DHCP manual list of IP addresses bound to a MAC address in any way and hit save, the router resets, which changes my public IP address. For a number of reasons, I can't get an affordable static IP (it would cost me an additional $35/month). Is there any chance that merlin does *not* reset the router and trigger an ISP to change external IP address when performing this most basic of router functions?

I spent about ten minutes trying to think of a way to search for the answer to this in existing posts and gave up.

 

[eibgrad]

Why does it matter if your public IP changes? If it's for remote access purposes, and you're using DDNS, that domain name will be updated accordingly. At worst it could temporarily upset active remote connections. But is that a substantial problem for you?

 

[DJones]

I'm on an AXE16000 router. Mostly I've been fine with the stock firmware, but there is one thing that would definitely move me to switch to merlin:

My ISP only provides me with a dynamic IP address. Whenever I modify the DHCP manual list of IP addresses bound to a MAC address in any way and hit save, the router resets, which changes my public IP address. For a number of reasons, I can't get an affordable static IP (it would cost me an additional $35/month). Is there any chance that merlin does *not* reset the router and trigger an ISP to change external IP address when performing this most basic of router functions?

I spent about ten minutes trying to think of a way to search for the answer to this in existing posts and gave up.

As far as I’m aware Merlin and Gnuton should not be resetting your wan ip address. That said a reboot usually is required manually to enforce the changes to dhcp.

I would suggest you use a DDNS their free ones like noip. That will allow your dynamic wan ip address to stay synced to a domain and you can port forward whatever you want lan side to be accessible.

 

[bbunge]

I'm on an AXE16000 router. Mostly I've been fine with the stock firmware, but there is one thing that would definitely move me to switch to merlin:

My ISP only provides me with a dynamic IP address. Whenever I modify the DHCP manual list of IP addresses bound to a MAC address in any way and hit save, the router resets, which changes my public IP address. For a number of reasons, I can't get an affordable static IP (it would cost me an additional $35/month). Is there any chance that merlin does *not* reset the router and trigger an ISP to change external IP address when performing this most basic of router functions?

I spent about ten minutes trying to think of a way to search for the answer to this in existing posts and gave up.

One way to get around that is to reserve a pool of IP addresses in the DHCP and use that reserved pool to assign static IP addresses at each client. For example, set the LAN/DHCP Server/IP Pool Starting Address to 192.168.50.50. That will allow you 48 IP addresses to use for static addressed clients. Once assigned you will not have to rely on DHCP to manage the addresses. Also, should you have to reset or change the router you will only need to change the IP Pool Starting address. Much cleaner way to manage clients that need a fixed address.

 

[RMerlin]

Asuswrt restarts the networking stack when setting new DHCP reservations, probably in an attempt to force clients to renew their leases. Asuswrt-Merlin does not.

 

[Qwinn]

eibgrad: I should have mentioned that I already have a DDNS (I use the router's asuscomm.com for that actually), but I have a particular use case where DDNS won't work. A use case where my activity/contribution is tracked by IP only, no capability to have them track by domain as of yet.

bbunge: I greatly dislike assigning static addresses. This requires having to reconfigure every device individually any time I want to change anything, including and especially DNS servers. No, as far as I'm concerned, binding MAC addresses via DHCP is the only way to go in that respect.

DJones: "That said a reboot usually is required manually to enforce the changes to dhcp." - well, if that really is necessary, that would explain why the stock firmware effectively resets the router for you. But talking with other people with non-Asus routers, they all seem shocked at the idea that modifying DHCP table would reset or require a reboot. *shrug*

 

[Qwinn]

Asuswrt restarts the networking stack when setting new DHCP reservations, probably in an attempt to force clients to renew their leases. Asuswrt-Merlin does not.

Oh, fantastic. I'll be spending some time this weekend installing some firmware then. Thank you!

(I'm not concerned about existing network connections needing to reset to renew leases. 95% of the time I'd just be adding a new entry, not modifying an existing one.)

 

[DJones]

eibgrad: I should have mentioned that I already have a DDNS (I use the router's asuscomm.com for that actually), but I have a particular use case where DDNS won't work. A use case where my activity/contribution is tracked by IP only, no capability to have them track by domain as of yet.

bbunge: I greatly dislike assigning static addresses. This requires having to reconfigure every device individually any time I want to change anything, including and especially DNS servers. No, as far as I'm concerned, binding MAC addresses via DHCP is the only way to go in that respect.

DJones: "That said a reboot usually is required manually to enforce the changes to dhcp." - well, if that really is necessary, that would explain why the stock firmware effectively resets the router for you. But talking with other people with non-Asus routers, they all seem shocked at the idea that modifying DHCP table would reset or require a reboot. *shrug*

By enforce I mean if another device is already utilizing that ip space a manual or stock firmware forced reboot would kick all devices off and order them as applicable to your router Mac or client ip based lan static dhcp leases. If you have Mac randomization enabled and are using router Mac based static ip addresses then be aware that client devices with this privacy feature enabled may take on their own ip address unless they are statically set per client also or MAC address randomization is turned off on client devices.

You might be able to get around reboots to “enforce” changes by restarting just the dhcp service instead. Or physically kicking eg. unplug/disable network for the conflicted devices taking them off the network then letting them back on which should detect dhcp changes or by rebooting just the devices. But as merlin said stock firmware probably restarts the network stack to “enforce” changes or reboots. It’s been a long time since I’ve been on stock so I’m unaware what it does exactly.

Restarting dhcp does not affect your wan ip address.

 

[Qwinn]

Nice, I hadn't seen a screenshot of the merlin GUI yet. Looks very cool.

One thing I'm curious about - I personally don't like to use the TrendMicro services, and prefer not to grant them permissions. The only feature that annoys me for losing is the Traffic Analyzer, specifically the Bandwidth Monitor page (and I find it ridiculous that I should have to grant any permissions to anyone for information as low level and basic as how much down/up each box on my network is using). I did notice though, that after a reboot of the router, even if TrendMicro doesn't have permissions granted, you *can* go to the Bandwidth Monitor page and it'll work as long as you don't touch any other setting or use any feature that involves TrendMicro (which seems to "wake it up" and shut the BW Monitor down if you haven't granted permissions). Can I get away with that in merlin as well?

 

[DJones]

Nice, I hadn't seen a screenshot of the merlin GUI yet. Looks very cool.

One thing I'm curious about - I personally don't like to use the TrendMicro services, and prefer not to grant them permissions. The only feature that annoys me for losing is the Traffic Analyzer, specifically the Bandwidth Monitor page (and I find it ridiculous that I should have to grant any permissions to anyone for information as low level and basic as how much down/up each box on my network is using). I did notice though, that after a reboot of the router, even if TrendMicro doesn't have permissions granted, you *can* go to the Bandwidth Monitor page and it'll work as long as you don't touch any other setting or use any feature that involves TrendMicro (which seems to "wake it up" and shut the BW Monitor down if you haven't granted permissions). Can I get away with that in merlin as well?

Most likely if you could get away with that in stock it will function the same in Merlin. Trend micros engine is a sorta black box Rmerlin has no control over so whatever it does or doesn’t do is speculation.

You will have more ways of monitoring processes with merlin via ssh packages addons by typing “amtm” or you can independently install entware packages using “opkg” so you will have more flexibility assuming the packages are compatible within the ARM instruction set. Example would be opkg install htop.

Okpg entware will only pull arm compatible packages. But if you install something manually outside of entware you’ll have to make sure it’s compatible with the kernel version and arm set.

 

[RMerlin]

Nice, I hadn't seen a screenshot of the merlin GUI yet. Looks very cool.

That's not Asuswrt-Merlin itself, that's a third party addon.

 

[DJones]

That's not Asuswrt-Merlin itself, that's a third party addon.

True, but the general UI is what is used in Asuswrt-Merlin.

For feature descriptions.

Home | Asuswrt-Merlin

www.asuswrt-merlin.net

For reference to the Qwinn scmerlin was just showing to display the ease of restarting different services. As Rmerlin stated that in itself is not Asuswrt-Merlin but a addon amongst many available.