Putty SSH Pfsense

bisssane

I can not access my Pfsense with SSH using PUTTY , it shows me this message: putty couldn't agree a key exchange

PS : I updated putty, but it did not work

JKnott

SSH can be configured to use public/private key pairs. You generate a private key for the client and matching public key for the server. With this, SSH can securely connect without requiring a password. There is a process for creating the keys in PUTTY and then you'd have to copy the public key to pfSense.

jimp

Upgrade your PuTTY client version. You must have a really, really old version of PuTTY installed.

bisssane

@jimp
no i have the last vesrion

jimp

And what version does the client report?

The exact issue you report is the same as what happened two years ago when we made changes that obsoleted some old and weak ssh key exchanges.

See Also:

https://www.netgate.com/docs/pfsense/releases/2-3-2-new-features-and-changes.html#SSH_Daemon
https://forum.netgate.com/topic/103276/ssh-couldn-t-agree-a-key-algorithm-available-curve25519-sha256-libssh-org/7

For everyone else, updating PuTTY fixed the problem.

If it didn't, then either your PuTTY isn't updating or maybe you're not hitting the ssh daemon on pfSense but something else entirely.

Gertjan

Sthis :
@bisssane said in Putty SSH Pfsense:

I updated putty, but it did not work

puzzles me.

The update didn't work ?
What is the Putty version now ? It should be 0.70 https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

jimp

Yes and I have seen before where installing the new PuTTY still leaves behind the old one, and doesn't update the icons, since depending on how it's installed it may be version-specific. Make sure to uninstall the old PuTTY first.

JKnott

@jimp said in Putty SSH Pfsense:

The exact issue you report is the same as what happened two years ago when we made changes that obsoleted some old and weak ssh key exchanges.

In that case, generating new keys, using the newer key exchanges should correct the problem. The issue is with the keys, not the app. I don't use Putty very often but, on Linux, I can select the key method when I create the keys.

jimp

In this case it's the key exchange protocol PuTTY can't use, not the keys themselves.