Janmesh.net > Documentation - How to turn an old modem router into a Janmesh wifi repeater

Turn an old modem router into a Janmesh wifi repeater and cjdns connectivity hub

Maybe you've got one useless old modem/router that can be used to connect to internet. Here, will convert one of them, namely a DLink dsl 2740B, into a dumb wifi access point (AP) that will operate open ad-hoc wifi, olsrd, and cjdns, in order to extend the range of a Janmesh network, and will distribute the mesh connectivity to the whole home lan network, simply by being pluggued through ethernet in your home Internet Box.

Find the right firmware for flashing

First off we head on to https://openwrt.org/toh/d-link/dsl-2740b. The sticker at the rear of the router says "hw version : F1" which is supported by OpenWRT up to version 19.07.2. Then we can

Download the flash image.
Press and hold the reset button
Power on the device
Wait until the power LED turns solid (after about 30 seconds)
Browse to http://192.168.1.1/
Login as admin, password admin
Maintenance -> firmware update
Upload the image

Basic configuration

If you get into serious trouble, remember that you can always use the reset button and restart from here.
log in at http://192.168.1.1 , as root, with empty password, and set a new password. Edit the wireless (network) : select Add then
Mode: Ad-Hoc
SSID: http://janmesh.net
add "lan" to networks associated with this interface

Tip: You may want to prevent low ACK disconnect in the 'advanced' tab.
apply pending changes and enable wifi interface
We now want to integrate the DLink into the lan infrastructure in order to have it able to reach internet. Most lan networks have a DHCP server running that can configure connections for a new network device.
All we have to do is to set up the ethernet interface to act as a DHCP client :

Network->interfaces, edit lan, set DHCP Client instead of Static Adress in "Protocol", apply pending changes

Locate by scan or in your main modem-router (box) admin panel the newly DHCP-assigned new ip adress of the dlink, and point your browser to it.

Network diagnostics should now ping.
System->software-Update list, then install olsrd and cjdns packages
You now got a Janmesh range extender, ethernet autopeerer box, fully fonctionnal.