2 ms·
> Fortunately, it's easy to solve: just use an SSH CA Sure, you could use SSH certificates, but that does mean deploying user certificates to your users and se
by alwillis 3y ago
> Fortunately, it's easy to solve: just use an SSH CA
Sure, you could use SSH certificates, but that does mean deploying user certificates to your users and server certificates to your servers, etc. And for some use cases, this would be the right thing to do.
Yes, a 10,000 person enterprise with dozens of servers should use SSH certificates. On the other hand, using SSHFP is also a viable solution, depending on the use case. In general, it's less work than creating a SSH CA, signing keys, distributing certificates, etc, especially when SSH certificates would be overkill.
On the other hand, with SSHFP, you run ssh-keygen -r examplehost.example.org and add the records to the server's DNS configuration.
On the client side, a user adds VerifyHostKeyDNS yes to their OpenSSH configuration and they're done.
> Why would you give the United States Government a say in whether you trust your own server? It's your own server!
SSHFP records are just the fingerprint of the server's public keys—no 3rd party has a say in the ssh-keygen command generating the records. I just made some SSHFP records—no government involved:
SSHFP <KEY-ALGO> <HASH-TYPE> <FINGERPRINT>
localhost IN SSHFP 1 1 78aefcdf726dfd71160c8dd9e31b385174da4189
localhost IN SSHFP 1 2 830313e0f1c70de6db7431f22f488e715f5882b7ad82a11bcb0b784fba618cfc
localhost IN SSHFP 3 1 8140d1ed33ee45e0d078e1c0ef61df03332eac5c
localhost IN SSHFP 3 2 748fdd9a6795626ec4c201cc41fb62c7407227db3e810e1a26d2e0b8cb82e896
localhost IN SSHFP 4 1 c75294aa5909c2dbfcd5606005bc4f2d1ec37ff6
localhost IN SSHFP 4 2 795480afe1777c3438f40bc269c25667cf366ef24c14f264456ff10844b818fb
KEY-ALGO Algorithm
0 reserved
1 RSA
2 DSA
3 ECDSA
4 ED25519
5 unassigned
6 ED448
HASH-TYPE Algorithm
0 reserved
1 SHA1
2 SHA256
The role that DNSSEC plays is ensuring that when a SSH client does a DNS lookup, it can trust the DNS reply hasn't been tampered with.