Configuring Guest Network in Asuswrt-Merlin and Asuswrt

If you are reluctant to give out your WiFi password to your guests who want to borrow your WiFi to get their mobiles devices to connect to the Internet when they are visiting your place, you can set up a Guest Network for them.

Guest Network is a useful function to allow guest or public Internet access while separating them from your own internal network. Asus Guest Network also has some advanced features for you to impose restrictions such as access time, bandwidth limiting, MAC filter, etc.

The Guest Network function in Asuswrt-Merlin firmware should be the same as in original Asuswrt firmware. It allows you to configure up to 3 separate Guest Networks for 2.4GHz wireless band and up to another 3 separate Guest Networks for 5GHz wireless band.

If your Asus router has two 5GHz wireless bands, then you'll have yet another 3 separate Guest Networks for your second 5GHz wireless band.

It is advisable for you to set an SSID for Guest Network that is different from your regular WiFi SSID.

If you set the Authentication Method to "Open System", anyone around your wireless router can connect to your Guest Network without the need of any password. It is advisable to set the Authentication Method to "WPA2-Personal" and set the WPA Pre-Shared Key as the password to connect to your Guest Network, which can be different from your regular WiFi password.

You can optionally restrict the Access Time of this particular Guest Network. For example, if you set the Access Time to 2 hours, the Internet access for this Guest Network will be cut off 2 hours after you clicked on the Apply button.

You can also optionally limit the Download Bandwidth and/or Upload Bandwidth for this Guest Network. If you set the value to 0 Mb/s or higher than your Internet access bandwidth assigned by your ISP, then it is not restricted.

If you enable Access Intranet, the devices connected to this Guest Network is able to access to networked devices connected to any of the LAN ports of your Asus router. If you use a switch to expand the network linked to a LAN port, all the devices connected to the switch are also accessible by the Guest Network. In this way, your Intranet is exposed to your guest.

If you disable Access Intranet, your guest won't be able to access to any networked devices connected to the LAN ports of your Asus router. However, they can still access to the devices connected to your WiFi, including those connected to your regular WiFi network.

If you want to also disable access to your WiFi connected devices, you can Set AP Isolated for a particular wireless band under Advanced Settings > Wireless > Professional. However, this setting is not Guest Network specific, and will affect all the devices connected to that particular wireless band.

If you want to only isolate the Guest Network from other wireless devices, you can explore into YazFi expansion for Asuswrt-Merlin. You can click here to find out more information about YazFi expansion in SNBForums, including its installation method and sample configuration file.

You can also optionally make use of MAC Filter to specify which mobile devices is allowed or not allowed to connect to this particular Guest Network.

Update firmware of Asus wireless router to the enhanced Asuswrt-Merlin version

Asuswrt-Merlin is a 3rd party enhanced version of Asuswrt, which is the official firmware in used by all recent Asus wireless routers. Asuswrt was originally forked out from the Tomato-RT/Tomato-USB firmware, which in turn developed base on the codes of Linux-based HyperWRT, a 3rd party enhanced firmware for Linksys routers.

Asuswrt-Merlin is mainly developed and maintained by Eric Sauvageau (a.k.a. RMerlin) based on the Asuswrt firmware developed and maintained by Asus technical team.

Asuswrt consists of open sourced GPL codes as well as closed source proprietary components. Asus releases the source codes of Asuswrt firmware in their website, with the closed source portion included as compiled binary codes. This GPL release includes everything needed to completely recompile a working firmware, with the exact same features as found in their firmware releases, making it possible to enhance it into Asuswrt-Merlin firmware.

The general goal of Asuswrt-Merlin project is to provide an alternative to the original firmware, and remain in sync with Asus's own development of each firmware release, so that new features and bugfixes development in original Asuswrt firmware can be trickled down into the subsequent Asuswrt-Merlin firmware.

Asuswrt-Merlin is intended to improve but not to replace the original Asuswrt firmware functionality. Its priorities are: Stability > Performance > Additional Features.

The website of Asuswrt-Merlin is https://asuswrt.lostrealm.ca, and you can click here to view the list of its enhancements made on top of the original Asuswrt firmware.

There is an Asuswrt-Merlin forum in the SNBForums for community discussion and support of this firmware, and RMerlin himself is an active participant and moderator there.

To date, Asuswrt-Merlin is made available and supported for the following Asus wireless routers:

• RT-AC66U_B1
• RT-AC68U, RT-AC68P, RT-AC68UF, RT-AC1900, RT-AC1900P
• RT-AC86U, RT-AC2900
• RT-AC87U
• RT-AC88U
• RT-AC3100
• RT-AC3200
• RT-AC5300

You can check for new release of Asuswrt-Merlin firmware at the following places:

• If your router is already installed with Asuswrt-Merlin firmware, you can check for new firmware version by clicking the Check button in Administration > Firmware Upgrade > Firmware Version in the firmware's web GUI.

• By manually checking at the Current Release information at the Asuswrt-Merlin website.

• By manually searching for new topic in Asuswrt-Merlin forum with title "[Release] Asus-Merlin 384.x is now available".

You can click here to go to the download webpage of Asuswrt-Merlin firmware in its website, or click here to go to its main download site at SourceForge.

At the SourceForge download site, select your Asus router model correctly, then select Release, and download the latest version of firmware accordingly. The firmware is packaged in a ZIP file.

After the download, you need to unzip the file. Before uploading the firmware file to your Asus router, it is advisable for you to check for its SHA256 signature and match it with the checksum information inside the sha256sum.sha256 file. This is to make sure you won't upload a corrupted file to your router and potentially brick the router.

The easiest way to perform a file checksum in Windows is by using 7-Zip. Once you have installed 7-Zip in your Windows computer, you can right click on the file, select "CRC SHA" and then select "SHA-256" to get the SHA256 signature of the file.

If you want to install Asuswrt-Merlin firmware into a new router, make sure you have gone through the Quick Internet Setup wizard to get the initial configuration of the original firmware. You don't need to do this if you are installing to router already in used, be it currently running on original Asuswrt firmware or Asuswrt-Merlin firmware.

It is advisable for you to manually record down your major settings by using printscreen, and also make a backup of your existing settings by going to Administration > Restore/Save/Upload Settings. Save both your Router Settings and JFFS Partition (the later might not be applicable to stock firmware) to your local computer.

Then, you can proceed to go to Firmware Upgrade section, click on Choose File, select the Asuswrt-Merlin firmware file which you have downloaded, and Upload it to your router. The firmware updating process will begin, and your router will be rebooted.

Normally, your router will be up-and-running with no lost of previous settings after the firmware update. If you find it not working properly, you can try to Initialize your router to Factory Default, take out your printed screens and redo all your settings from scratch. If you still facing any problem, you can go to SNBForums and seek for help there.

Heat dissipating solution for Asus RT-AC86U router with USB cooling fans

The Asus RT-AC86U wireless router has a stand-up design and its heat management is relying on passive cooling.

Unlike those flatbed routers which we can easily provide heat dissipating solution to them by using normal laptop USB cooling fans, the temperature management solution for this stand-up router needs some tweaking to attach external fans to it. Luckily, there is ready made solution in the market, and it is quite cheap too.

If you are using AsusWRT-Merlin firmware in the router, you are able to read the runtime temperature reported at its Broadcom BCM4709 processor (CPU), Broadcom BCM4365E 2.4GHz WiFi SoC chipset and Broadcom BCM4366E 5GHz WiFi SoC chipset respectively.

In normal operation, the temperature at 2.4GHz WiFi chipset stays around 50-55 degree Celsius and the temperature at 5GHz WiFi chipset stays around 55-60 degree Celsius. However, the dual-core CPU temperature is always on the high side, staying above 70 degree Celsius, and there are users reporting that it can go up to above 90 degree Celsius.

If you are feeling uncomfortable with these kind of temperature readings and would like to lower them down to a more comfortable level, you just need to install a pair of external USB cooling fans at the back of the router.

The two 7cm fans are powered by 5V DC from the USB 2.0 port of the router itself. You can also plug it to the router's USB 3.0 port, but that port is normally used by external storage, USB Internet dongle, etc.

It is attached to the back of the router using 3M double-sided tape provided in the cooling fans set package.

Within 20 minutes, the pair of fans are able to cool down about 5 degree Celsius to both the 2.4GHz and 5GHz chipsets respectively. They can effectively cool down the temperature of the CPU by a whopping 20 degree Celsius.

With this heat dissipating solution, now the temperature at the 2.4GHz chipset reduced to around 45 degree Celsius, and the temperature at the 5GHz chipset reduced to around 52 degree Celsius. The CPU temperature greatly reduced to around 53 degree Celsius.

If I power down the fans by unplugging it from the router's USB port, all the 3 temperature readings will gradually increase, and went back to the previous high level within 20 minutes.

The fans are rotating at relatively low speed at 2100 RPM, making them pretty quiet. You can hardly hear their noise unless putting your ear very close to them during silent night.

According to their specifications, their noise level is at 18 dBA only. Their lifespan is around 50,000 hours, which is equivalent to over 2000 days, long enough to serve for the entire lifespan of the router.

Other than Asus RT-AC86U, this pair of USB cooling fans can also be used for Asus RT-AC68U router as both of them are having very identical size and casing build.