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doc:appunti:linux:sa:ssh_config

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SSH Config

No matching key exchange method

Problem connecting from a Debian 11 Bullseye to an old OpenWRT Chaos Calmer:

ssh root@192.168.31.45
Unable to negotiate with 192.168.31.45 port 22:
    no matching key exchange method found.
    Their offer: diffie-hellman-group14-sha1,diffie-hellman-group1-sha1,kexguess2@matt.ucc.asn.au

You can edit your $HOME/.ssh/config file and put ah Host stanza like this:

Host hostname hostname.domain.tld 192.168.31.45
    KexAlgorithms +diffie-hellman-group1-sha1

This will force the use of diffie-hellman-group1-sha1 key exchange method, which is considered less secure nowday.

No mutual signature algorithm

Problem connecting from a modern (2022-02) Termux environment to an old Debian 6

ssh -o HostKeyAlgorithms=+ssh-rsa -o PubkeyAcceptedKeyTypes=+ssh-rsa root@192.168.0.250
doc/appunti/linux/sa/ssh_config.1646068446.txt.gz · Last modified: 2022/02/28 18:14 by niccolo