RSA, DSA and ECDSA host keys Server! version: 4.0.0+

Our users are aware that old Server! versions (from 1.0 to 3.x) used to support only a single host key, and it had to be an RSA key.

As of version 4.0, though, Server! supports RSA, DSA, and ECDSA host keys, and it support multiple (unlimited) host keys per virtual server.

The addition of DSA keys was mostly driven by the fact that some of our customers possess legacy DSA host/server keys that they are required to use, in order for certain client applications to work properly. The addition of ECDSA host keys instead is a truly remarkable new feature, and to understand why just check out the comparison table here below: Continue reading

SSH Server Key: best practices

Upon installation, Server! auto-generates a 1024 bit SSH Server Key, and that is enough for most users and most scenarios.

But some of our users may have higher needs in terms of bit-length (2048 or even 4096) or may need to use a specific SSH Server Key provided by a third party. This article covers such scenarios.

If you only need a higher bit-length, the easiest way is to generate a new SSH Server Key from within the Configuration Manager. In order to do so, simply click the “gear” button next to the SSH Server Key field, as shown in the picture below: Continue reading

RSA or DSA keys for public-key authentication with Server!?

Some SFTP clients have the ability to generate key-pairs for SSH2 public-key authentication, and – in some cases – our users are presented with the question: do you want to generate RSA or DSA keys?

When you want to authenticate against a Server!, please, always use RSA keys. If you use DSA keys you may not be able to successfully authenticate.