Dexter Networking

Dexter has an RJ-45 connector for CAT5 Ethernet connection. Because of issues with the Linux stack, WiFi adapters are not supported (as of April 2018). Although Dexter does have the ability to connect directly to the internet via a CAT5 cable to a local router, the easiest way to connect from a PC is to simply connect that CAT5 cable directly between the network port on the PC and Dexter. This is perfectly acceptable and works very well. The network adapter on the PC should be configured to the 192.168.1. network. In the past, Dexter has defaulted to 192.168.1.142 so any other address is fine for the PC adapter. The PC's wifi adapter can remain connected to local WiFi at the same time.

In the future Dexter will use DHCP, and so it's IP address will be whatever is assigned by the router if it is network connected. Your computer configuration needn't change. You can log into your router and look at the connected devices to find it, or

• Android or iOS Smartphone: Install and use the Fing app
  https://www.fing.io/
• on Linux / Mac use arp -a. You may need to ping broadcast first. Or sudo apt-get nmap and then nmap -rP _ip_/24 where ip is your local network address. e.g. 192.168.1.1
• on Windows, arp -a returns the ip address, but no machine names. Or you can download and install
  http://www.advanced-ip-scanner.com

Once you are connected, you can shell into Dexter to update the firmware or do development in the onboard Linux OS, or just connect via DDE to develop and run jobs.

To SSH into Dexter, you will need an SSH client (e.g. PuTTY). Configure the IP address in the client software to Dexter's address, set the port to 22, and select SSH.

Username: root
password: klg

Dexter provides a SAMBA share and an sFTP service for transferring files back and forth, in addition to the socket connection for commands via DexRun. Access the share at \\<dexters-ip>\share.

You can also transfer files via the /usr/lib/openssh/sftp-server service but you will need to supply the same username and password. And you will need a client which supports sftp such as
https://winscp.net/eng/download.php
If you wish to disable or reconfigure the sftp daemon, see the /etc/ssh folder.

You generally should NOT need to actually give Dexter access to the internet, but if you need that for some reason, you will need that CAT5 cable to run between Dexter and your Router. After a restart, Dexter should automatically connect and have internet access. You can test that with ping www.google.com (press Ctrl+C to stop). If it works, great! If not, here are some common errors and how to resolve them.

• "Network is unreachable" There is no internet connection. Check that Dexter is on the same network as your router. E.g. If your local network is 192.168.0. you will need to edit the IP address in both Dexter and DDE. In Dexter, sudo nano /etc/network/interfacesand edit the IP there. In DDE, you will need to change the default address for your Dexter robot in the dde_init.js file in your documents dde_apps folder. e.g. persistent_set("default_dexter_ip_address", "192.168.0.142")

• "Unknown host" The DNS system could not resolve the name to an IP address. Try ping 8.8.8.8 instead. If you CAN ping 8.8.8.8 but still have no DNS (e.g. ping www.google.com) fails, then try adding nameserver 8.8.8.8 to a file called /etc/resolvconf/resolv.conf.d/base e.g. sudo nano /etc/resolvconf/resolv.conf.d/base type in
  nameserver 8.8.8.8 save it, and then restart.

See also:

• https://help.ubuntu.com/lts/serverguide/network-configuration.html General information on Network configuration for servers. Dexter is basically a server.