RT-AC86U Manually Assigned IP Limit is 64

[dennyfmn]

I have been running an RT-AC66U with version 376.47. For quite a while with 70 some manually assigned addresses.
Manually Assigned IP around the DHCP list (Max Limit : 128)

I am in the process of upgrading to an RT-AC86U running the current release 386.5_2.
I was surprised to see the limit was reduced to 64.
RT-AC86U 386.5_2 Manually Assigned IP around the DHCP list (Max Limit : 64)

When I tried to populate the table from a text file from the old router, it threw a segfault error.
nvram set dhcp_staticlist="`cat dhcp_static2.txt`"

Since a have a bit over 70 manually assigned addresses in the old router, I would like to preserve them on the new router.

Can this be returned to a limit of 128?

Thanks!

 

[Jeffrey Young]

Use the /jffs/configs/dnsmasq.conf.add script and use the dhcp-host directive instead.

 

[dennyfmn]

Use the /jffs/configs/dnsmasq.conf.add script and use the dhcphost directive instead.

That would be a work-around, but much less convenient than using the web interface.
Would it be a big deal to put the limit back to 128?

 

[Jeffrey Young]

Using the web interface to retype 70+ hosthames each time you have to do a manual setup compared to using a pre-configured script that can be easily copied in?

 

[Jeffrey Young]

You can check out Jack's DHCP script. It allows for import and export options. That script may allow you more than 64 hosts.

 

[dennyfmn]

Using the web interface to retype 70+ hosthames each time you have to do a manual setup compared to using a pre-configured script that can be easily copied in?

I'm not typing anything.

Export from old router:
nvram get dhcp_staticlist > dhcp_static.txt

Copy txt file to new router and import it:
nvram set dhcp_staticlist="`cat dhcp_static.txt`"
nvram commit

Once the table is loaded, maintaining the list from the web interface is much easier.

 

[dave14305]

The absolute max characters is now 2500 on your new router. And I believe the format has changed slightly since your ancient 376 version to include a DNS server field, so your export would be incompatible as-is.

webui: harmonize dhcp_staticlist length with upstream · RMerl/asuswrt-merlin.ng@9cde975

Upstream is 2500, and we had it set at 2999, which would fail on HND models when going over 2500.

github.com

webui: label hostname as optional on DHCP static leases; reduce max s… · RMerl/asuswrt-merlin.ng@0d4641c

…tatic leases to 64 to better handle the hardcoded max length of 2500 bytes

github.com

 

[Jeffrey Young]

I'm not typing anything.

Export from old router:
nvram get dhcp_staticlist > dhcp_static.txt

Copy txt file to new router and import it:
nvram set dhcp_staticlist="`cat dhcp_static.txt`"
nvram commit

Once the table is loaded, maintaining the list from the web interface is much easier.

You are assuming nvram variables remain the same across software versions. That is not a good assumption to make. Things change.

 

[dennyfmn]

The absolute max characters is now 2500 on your new router. And I believe the format has changed slightly since your ancient 376 version to include a DNS server field, so your export would be incompatible as-is.

webui: harmonize dhcp_staticlist length with upstream · RMerl/asuswrt-merlin.ng@9cde975

Upstream is 2500, and we had it set at 2999, which would fail on HND models when going over 2500.

github.com

webui: label hostname as optional on DHCP static leases; reduce max s… · RMerl/asuswrt-merlin.ng@0d4641c

…tatic leases to 64 to better handle the hardcoded max length of 2500 bytes

github.com

Ok, thanks for the details. I guess I'll use the dhcp-host directive at least for some of my systems that are not expected to change. I was not aware of an nvram format change. Thanks!

 

[dennyfmn]

You can check out Jack's DHCP script. It allows for import and export options. That script may allow you more than 64 hosts.

Interesting. Where can I find that? I looked in Merlin Add-ons and couldn't find it. Thanks, I'm a noobie here...

 

[Jeffrey Young]

I think you can install from AMTM.

I find the config so much easier as I also use other custom settings in dnsmasq to integrate my Active Directory into my network.

 

[Crimliar]

SSH into the router
run amtm
and I think its option j7

 

[dennyfmn]

I think you can install from AMTM.

I find the config so much easier as I also use other custom settings in dnsmasq to integrate my Active Directory into my network.

Thanks, I'll check it out...

 

[dennyfmn]

SSH into the router
run amtm
and I think its option j2

Great, thanks for the tip...

 

[heysoundude]

You can check out Jack's DHCP script. It allows for import and export options. That script may allow you more than 64 hosts.

It allows me 253 hosts on my AC86. OP should get similar

 

[RMerlin]

Would it be a big deal to put the limit back to 128?

nvram limitations is the issue preventing extending this. That variable max length cannot be increased on the RT-AC86U.

 

[dosborne]

Maybe examine closely your reasons for actually needing more than 64 entries on a home router? There may be other options or configurations that are better suited, or a higher end router.

 

[JGrana]

Personally, I use YazDHCP. Once installed, it “enhances” the standard DHCP Server WebUI page so it looks like the Asus version on steroids. As other have said, it allows you to export and import your entire list. You can assign the hostname and optionally a different DNS server.
Works well.

 

[bennor]

Interesting. Where can I find that? I looked in Merlin Add-ons and couldn't find it. Thanks, I'm a noobie here...

Run AMTM from the router SSH command line interface; its one of the options in there (j7 for me). Or manually install it. See the dedicated thread topic for YazDHCP in the Add-On's subforum.

YazDHCP - feature expansion of DHCP assignments (increasing limit on the number of DHCP reservations)

Or see the dedicated GitHub page for YazDHCP.

https://github.com/jackyaz/YazDHCP

Once installed one can export/import from the router GUI interface's LAN > DHCP Server page. Example:

 

[Crimliar]

It is indeed J7 (not J2). The only 2 devices I have on the LAN here that have fixed local IP addresses are running Pi-Hole filtering DNS servers. Everything else that I need to access from a browser is set up in the Pi-Hole Local DNS such that I can use friendly names - a bit like having a supercharged hosts file!