Server HMAC algorithm not found

[ts678]

@DarthWeber

The also informed me that md5 is outstanded and a security problem, so they disabled it.

I agree, and had no intention of suggesting they turn it on. As noted:

@ts678

Usually what happens is a server starts denying the older crypto, so I tested an md5.

and yet they gave it to you on their big list? Or maybe a different source gave list here?

@DarthWeber

The server is commercial, i got the info i need to use one of

@DarthWeber

Is one of those MAC possible?

As noted:

@ts678

2024’s SSH.NET has them.
Duplicati hasn’t picked that one up yet.

so not possible now, and developer would have to speak about future. There’s a new ask for it:

Server HMAC algorithm not found #4674

We see the same issue with Duplicati SFTP after our latest round of SSH/SFTP server hardening, which removed the hmac-sha2-512 and hmac-sha2-256 MACs flagged as weak by ssh-audit due to their encrypt-and-MAC method.
So +1 from here to the suggestion about upgrading the dependency to SSH.NET 2024.x, which added support for a number of modern MACs.