From DD-WRT Wiki
Delivering Wi-Fi AC1750 dual band speeds with AC SmartBeam technology to your home network, the DIR-868L is the perfect solution for those looking to enjoy online gaming, multiple HD video streams, and fast file transfers – all with less wireless interference for maximum throughput.
|Radio (2.4 GHz)||BCM4331|
|Radio (5 GHz)||BCM4360|
|Antenna Type||External (Dual Band)|
- Specifications found on Smallnetbuilder.net 
- This specifications listed are of the Rev A model
 Installation Instructions
 Step-by-step instructions from out-of-the-box factory firmware
DD-WRT can be flashed directly on the D-Link DIR-868L by using the D-Link web interface:
- An older factory-to-ddwrt.bin version is required to successfully upgrade when running the factory firmware. Download a factory-to-ddwrt.bin firmware between 01-20-2015-r25974 .. 05-28-2015-r27096.
- Open the dd-wrt ftp, select a year and version and finally select the router revision (e.g. dlink-dir868l-reva when HW/ver is A1, dlink-dir868l-revb when HW/ver is B1, etc.) and download the dir-868*REV*-webflash.bin firmware file. WARNING: 08-24-2016-r30471 and later are currently reported broken.
- Open the D-Link web-interface (http://192.168.0.1) in a web browser, Log In, and go to Tools -> Firmware. *Warning: only flash over an Ethernet-cable.
- Select factory-to-ddwrt.bin and click the '"Upload'"-button. When the firmware has been successfully flashed, the router will reboot, this may take up to 3 mins. If the (top) Power-LED on the front of the router keeps blinking, see Recovery mode.
- The router address should now be changed into http://192.168.1.1. You may need to set your TCP/IPv4 settings manually using 192.168.1.1 as IP address and 255.255.255.0 as Subnet mask to access the router.
- Upgrade the router (again) by using the dir-868*REV*-webflash.bin firmware. * Note: The router doesn't support Hard Reset (aka 30/30/30 reset), select Reset to default or use the Erasing NVRAM method instead.
 How to restore to factory firmware
- Follow steps of Recovery Mode.
- When returned to factory firmware, navigate to Tools - System and select Restore Factory Settings.
 Recovery Mode
When the Power LED keeps blinking on boot, the router has entered the recovery mode. This usually happens when flashing a firmware went wrong, or the configuration has been corrupted.
It is also possible to (force) boot into recovery mode to restore a (soft-)bricked router or flashing back to the factory firmware:
- Download the latest available firmware on the official D-Link website of the router revision.
- Unplug all cables (incl. power cable) from the router.
- Connect the router to the PC using one of the 4 switch ports.
- Set the PC TCP/IPv4 address to 192.168.0.2 and use 255.255.255.0 as the Subnet mask.
- Disable any running firewall(s), anti-virus, TCP/IPv6, etc.
- Power-on the router with a paperclip pushing the hidden reset button located on the bottom of the device for a few seconds, when the Power LED starts blinking, release the reset button.
- Open Mozilla FireFox (*other browsers doesn't seem to work correctly when trying to flash the firmware) and navigate to http://192.168.0.1.
- Upload the stock firmware, when completed the router should report to reboot.
- The router should now be running stock and accessible on the default address. (http://192.168.1.1).
 Known Issues
 Bad WiFi drivers
DD-WRT has multiple issues with WiFi firmware.
- WiFi connect slow: you might experience slowness connecting your device to the AP. On Android it may hang at "Obtaining IP address" for around 10 seconds.
- 5GHz band issue: the 5GHz band might not pop up when you search for WiFi networks on your device or it will take a few seconds to show up (and disappear again). Try to manually add the wireless network or change the Channel Width of the 5GHz interface to Wide HT40 instead of VHT80 (altought this may affect performance).
If using the inbuilt OpenVPN-server in tunnel-mode, you may need to use the following firewall rules:
iptables -A INPUT -i vlan2 -m state --state NEW -p udp --dport 1194 -j ACCEPT iptables -A INPUT -i tun2 -j ACCEPT iptables -A FORWARD -i tun2 -j ACCEPT iptables -A FORWARD -i tun2 -o vlan2 -m state --state RELATED,ESTABLISHED -j ACCEPT iptables -A FORWARD -i vlan2 -o tun2 -m state --state RELATED,ESTABLISHED -j ACCEPT iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o vlan2 -j MASQUERADE
- Note 1: Verify that the interfaces are correct by running the ifconfig command
- Note 2: You may need to adjust the above IP-address (& netmask)
The following Additional DNSMasq Options may also be needed, to stop DHCP(-service) on the tunnel-port:
 D-Link DDNS
D-Link offers router owners a free dynamic DNS host name service (https://www.dlinkddns.com/). This service can also be enabled on the dd-wrt firmware:
|Username||Your username (no email-address)|
|IP Check||Yes *only when needed|
A working state should give verification messages, like this one:
Thu Jan 22 23:11:21 2015: INADYN: Started 'INADYN Advanced version 1.96-ADV' - dynamic DNS updater. Thu Jan 22 23:11:21 2015: INADYN: IP read from cache file is 'x.x.x.x'. No update required.