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## Background
I was trying to debug a service over `ssh` that offered password-only
authentication, but I couldn't seem to get the `ssh` client to prompt me for the
password.
It looked something like this (skip ahead to the conclusion if you're pressed
for time):
## Troubleshooting
```shell
λ ssh root@[redacted]
Unable to negotiate with [redacted] port 22: no matching host key type found. Their offer: ssh-rsa
```
But the same command was working just fine for my coworker.
I took a closer look with `ssh -v root@[redacted]`, but nothing jumped-out at
me. Maybe it's something with *my* `ssh` configuration; let's remove that
variable:
```shell
λ ssh -F /dev/null root@[redacted]
Unable to negotiate with [redacted] port 22: no matching host key type found. Their offer: ssh-rsa
```
> Ah it looks like there's a way to set my preferred authentication method...
> -- me
```shell
λ ssh -F /dev/null -o PreferredAuthentications=password root@[redacted]
Unable to negotiate with [redacted] port 22: no matching host key type found. Their offer: ssh-rsa
```
## Conclusion
Well it turns-out that newer SSH clients disable the `ssh-rsa` public key
signature algorithm because it depends on SHA-1, which is considered insecure.
```shell
λ ssh -V
OpenSSH_9.0p1, OpenSSL 1.1.1p 21 Jun 2022
```
...and according to the `ssh -v` output, the server is running a pre-COVID(!!!)
version of `ssh`:
```
debug1: Remote protocol version 2.0, remote software version dropbear_2018.76
```
So if you don't have time to upgrade the SSH server, and you just want to
connect, the following should work because we're *opting-into* the less secure
option:
```shell
λ ssh -o HostKeyAlgorithms=+ssh-rsa root@[redacted]
```
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