Update RT-AC68U firmware: 3.0.0.4.376.44_0 (Merlin build) to the latest version: 386.9_0

Hey, after upgrading to firmware 386.9_0 my firewall/network filter is acting weird.
In the previous "firmware" I had a firewall/network filter defined in such a way that I had a whitelist for ports 80, 443, 993, 25, 465 for IP: 10.0.0.4. Thanks to this, the Daughter had access only to websites and e-mail. Currently, when I have set up the web service filter, when the white list filter is running, all network devices are not allowed to access the internet, except for the IP address: "10.0.0.4", which has full access.
When I set the blacklist, the IP address: "10.0.0.4" is blocked and no internet access at all. It's as if port filtering doesn't work at all!
Is something messed up and can it be somehow checked in the router or I just don't understand the current principle of operation?

Attached is a screenshot of the configuration.

Greeno said:

Hey, after upgrading to firmware 386.9_0 my firewall/network filter is acting weird.
In the previous "firmware" I had a firewall/network filter defined in such a way that I had a whitelist for ports 80, 443, 993, 25, 465 for IP: 10.0.0.4. Thanks to this, the Daughter had access only to websites and e-mail. Currently, when I have set up the web service filter, when the white list filter is running, all network devices are not allowed to access the internet, except for the IP address: "10.0.0.4", which has full access.
When I set the blacklist, the IP address: "10.0.0.4" is blocked and no internet access at all. It's as if port filtering doesn't work at all!
Is something messed up and can it be somehow checked in the router or I just don't understand the current principle of operation?

Attached is a screenshot of the configuration.

Click to expand...

Just so people are aware, Greeno also has a separate discussion thread Firewall configuration for "www" and e-mail only that may contain information or posts relevant to Greeno's latest post here.

Yes it's true.
I'm sorry about this situation. Both threads merged together due to a "firmware" update.

Dear forum users. Since I can't get answers to the updated firmware questions, I'm wondering if I can downgrade the Merlin firmware to the following version: RT-AC68U_386.4_0. From what I can see is the latest version of the software, which weighs about 35MB and is from January 1, 2022, so it's not that old. Am I right that this version won't block grandpa RT-ac68u and it should be better, and if I'm wrong, what version should I install?

Can I easily change the firmware from version: 386.9_0 to 386.4_0 by updating the router in the traditional way and then restoring the factory settings?

With the firmware: 386.9_0, the router, from what I can see, cannot even handle the basic issue for which it is intended, i.e. routing. Currently, with a 1 Gb connection, the transfers I receive from the Internet are on average about 200 Mb / s, even when connected with a 1 Gb / s ethernet cable. I have problems with basic services: dlna (I can't map the contents of the disk, because the router hangs), something messed up with the firewall, which I write about in the previous post. In general, the firmware is very rich in features that I cannot use.

If for the next few years I can't use my grandfather RT-ac68u for work, then what router can you recommend me. Is it worth buying RT-AX86U and have equipment for the next, say, 5 years. I have had the RT-ac68 for 8 years. Do you recommend any other model of router?

Greeno said:

I'm wondering if I can downgrade the Merlin firmware to the following version: RT-AC68U_386.4_0. From what I can see is the latest version of the software, which weighs about 35MB and is from January 1, 2022, so it's not that old.

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Can you downgrade? Yes just do a hard factory reset and manually reconfigure (don't use a saved router config file) after firmware downgrade. Note that depending on the older firmware version certain add-on Merlin scripts may not support that older firmware version.

However not sure why you indicate 386.4_0 is the latest. The latest Asus Merlin release version firmware for the RT-AC68U is 386.9_0. For stock RT-AC68U Asus firmware the latest is 3.0.0.4.386.51255.

One word of warning on using older firmware. Older firmware won't have security updates and patches that later firmware will have. You could potentially, and very likely, be opening up your router to unpatched security vulnerabilities or other previously patched issues by downgrading to earlier firmware. Particularly if downgrading to a significantly older firmware version, in this case firmware more than a year old.

What I meant was that the firmware version: 386.4_0, was the last one, which was about 35 MB.
All subsequent ones occupy over 90 MB and clog up the grandfather.

Therefore, I am asking for a worthy successor.

Greeno said:

What I meant was that the firmware version: 386.4_0, was the last one, which was about 35 MB.
All subsequent ones occupy over 90 MB and clog up the grandfather.

Therefore, I am asking for a worthy successor.

Click to expand...

The bigger size of the latest verions is due to the inclusion of a separate firmware veersion for the AC68U v4, which has a different hardware. As far as I know, there is no relevant change in the firmware size for your older AC68U.

I'd recommend also to try a hard reset without restoring your saved settings. Reconfigure eveerythin manually and see how it goes. If this fails, only then I'd consider downgrading.

Performed a hard reset after updating to the latest software version (386.9_0). Everything was set up from scratch. I can try factory reset and reconfigure everything. However, I believe that the old man will clearly not be able to cope with such a large functionality of the current software and it will not change much.

If I understand your statement correctly, the firmware version: 386.4_0 will not change much when it comes to the load on the router and it will still be clogged with software.

Currently, both processor cores are working practically at the limit (100% utilization), the memory is also practically full. There is not much configuration. Basic configuration including several port forwarding rules and one openvpn server.

I will try to reset the router to factory settings again and do the whole configuration again. However, if it does not change anything, then what firmware version do I need to go back to so that the firmware does not burden the router so much.

I am also asking for information whether it is worth buying the RT-AX86U PRO router, for peace of mind I will gladly invest in new equipment. If not the RT-AX86U PRO, then what other model?

Well, it is an old router, so it may be just showing it's age. However, I have three AC68U configured for relatives that keep working perfectly well. One of them is running 386.9 without problems.

Of course, the "works well" assessment depends on your specific needs. It also it may be hampered by some specific configuration.

Greeno said:

What I meant was that the firmware version: 386.4_0, was the last one, which was about 35 MB.
All subsequent ones occupy over 90 MB and clog up the grandfather.

Click to expand...

How do you know your router is being "clog up" due to the later firmware firmware file size being larger? Its been pointed out (both by the post above) and elsewhere, the reason for the larger firmware file is the inclusion of seperate firmware for different RT-AC68U hardware revisions, likely the V4 version apparently. It should be noted the stock Asus firmware for the RT-AC68U also jumped in firmware size after the 2021/01/18 3.0.0.4.386.41634 firmware. Went from 40.41 MB to 91 MB with 3.0.0.4.386.43129. There was discussion about it here in the stock firmware subforum at the time. Your router will determine the correct version to apply when updating. RMerlin explains the larger firmware file size (here and here):

RMerlin said:

Because it contains two firmware images: one for the "traditional" RT-AC68U, and one for the forecoming RT-AC68U V4.

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RMerlin said:

I haven't examined the file to determine if the dual firmware file was properly generated in this particular case, but I can tell that it's Asus's intention to eventually have the RT-AC68U firmware image contain two different firmwares.

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Been using the larger firmware versions for the past few Merlin firmware releases on an old RT-AC68U without issue. Only issue recently when updating Asus Merlin firmware was low NVRAM in Alpha 386.9, but that was solved by a hard factory reset. Beyond that, router ran fine on release 386.9. Currently running the Beta 386.10 without issue. Router is configured for wireless router mode and running both YazFi and YazDHCP add-on scripts. I do not have AiProtection features enabled.

You're right, I'm not sure.
However, from the load parameters of the processor cores and memory, and the various types of problems I write about, I know that something is wrong in my case.
I'll try a factory reset first. But if this continues, if someone is able to write me, what version of the firmware should I go back to?
Unfortunately, due to various issues I'm facing at the moment, I can't afford many hours of setup, which I like anyway

Greeno said:

Currently, both processor cores are working practically at the limit (100% utilization), the memory is also practically full. There is not much configuration. Basic configuration including several port forwarding rules and one openvpn server.

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You should investigate what features or options you have enabled that are consuming so much of the processor and memory (RAM or NVRAM) if they are indeed as you indicate. Maybe the openvpn server is the cause? Edit to add: maybe do top from the SSH CLI to see what processes are using the processor and memory.

Not seeing a large consumption of processor or RAM on a RT-AC68U. (edit to add: on Asus Merlin firmware 386.10 Alpha)



The RT-AC68U is very long in the tooth. If you run a lot of scripts or processes or use it as a NAS/media server it may struggle. Considering it's age one may want to look into a newer more capable router if one plans on running lots of options or scripts or use it as a NAS/media server. Really though if one is using the router as a NAS/media server they should consider getting a dedicated NAS/media server so they don't tax their router's limited hardware.

Greeno said:

what version of the firmware should I go back to?

Click to expand...

Upgrade to the newer stock Asuswrt 386_51255 instead, do basic configuration and let the router run without touching it too much.

Dear forum users. Thank you very much for all the useful tips. I have twice reset the "Router" RT-ac68U to factory settings after updating the Merlin firmware to version 386.9. The processor and memory do not go crazy like before. Apparently there must have been some junk after the update, even though I did a factory reset once. Now almost everything works as it should. Unfortunately, I still can't deal with the minidlna server, every time I map videos I get an error and I have to disable it. It easily handles the mapping of music files, and there are about 8000 of them. Unfortunately, when mapping movies (and there are about 300 of them), the router hangs every time and I have to turn off DLNA.



Does anyone have an idea to map videos from the console via ssh, unfortunately it does not work via asus web manager.



I would also like to get support for the firewall section - network service filter. Can anyone check how the filter works on Merlin firmware version 386.9. In my case, as per the attached screenshot, it disables the Internet for all IP addresses except IP address: 10.0.0.4. And according to the applicable rule, this filter should provide services for the IP address within the range of ports indicated in it. The principle of operation is strange and completely different than before the update. This is also described differently in the whitelist and blacklist explanations.

Please repost in English.

Greeno said:

Unfortunately, I still can't deal with the minidlna server, every time I map videos I get an error and I have to disable it. It easily handles the mapping of music files, and there are about 8000 of them. Unfortunately, when mapping movies (and there are about 300 of them), the router hangs every time and I have to turn off DLNA.

Click to expand...

On the DLNA issue try checking the system log to see if it indicates an error or problem with MiniDLNA when you map the video. Also, check the video file names, could be special characters in the file name or metadata tags on the video files could be causing a problem.