Devolo Magic 2 wifi

Stable powerline connection on Devolo Magic 2 wifi mesh

Devolo Magic 2 wifi is a series of products made to create a mesh wifi network in your home with multiple wifi accesspoints connected to the router over the powerline network. It can sometimes be difficult to obtain a reliable, stable connection of the powerline as noise in the powerline can interfere.

This is how I make it as stable as possible.

  • Do not connect the powerline adapter via an extension cord. It should be connected directly to the outlet.
  • Try to find outlets as close to the fuse box as possible. Especially for the unit connected to the router, because this unit will need to communicate well with all other units on the network.
  • If possible, connect the units to outlets that belongs to the same phase. Even though connection over different phases should be possible, it gives lower throughput and more unreliable connection.
  • If possible, use grounded outlets only. This will make it possible for the device to use MIMO technology instead of instead of SISO. MIMO gives higher throughput and is more reliable. Screenshots: SISO mode (left) compared to MIMO mode (right).
    SISO mode MIMO mode
  • In the powerline configuration, deselecting Automatic compatibility mode (recommended) * and choosing VDSL 17a (default) seems to be most reliable for me. (In automatic mode the unit sometimes gets very poor connection and needs to be rebooted in my case.)
  • The kit came with one router unit and two client units. After a while I was moving things around and for a while I was only going to need coverage where one of the client units where located so I disconnected the other. Now, the wifi connection became very unstable for the clients, even though they were very close to the remaining unit. I just reconnected the disconnected Devolo unit and voila – the wifi connection became much more stable. Is it built into the design that there should be at least two Devolo units up and running?

Powerline ethernet and RFI

As an active radio amatuer (aka “ham”), I am very keen on using equipment that are not causing radio interference (RFI). The Devolo units seems to stay well out of amatuer radio shortwave bands, but on citizens band (CB, or 27 MHz), that is not the case. Heavy RFI can be heard on the 27 MHz band.

Is multiple CAA DNS-records allowed? Yes!

A client was about to renew one of their SSL certificates and the provider requested them to add a CAA DNS-record for the provider. The client already had one CAA DNS-record for another provider in their domain, becuase they where using different providers of SSL certificates for different purposes in their organization.

The CAA DNS-record for the provider in question was added but the provider said they couldn’t issue the certificate as long as there was another CAA DNS-record present. The provider claimed there can only be one CAA DNS-record present in the domain.

The provider might be correct in the sense of that the provider’s system can’t handle multiple CAA records but multiple CAA records is not a violation of the RFC! It is just the provider who can’t handle it and makes it the customers problem.

This might be a simple way of obstructing the client in using the provider’s competitors but the provider is not correct in their statement. According to RFC8659 there are no limitations in the number of CAA DNS-records in one domain. The provider should just look for their CAA DNS-record in the client domain DNS-records and ignore competitors records.