SSH problem from BasicLinux floppy booted 486 to Fedora 25

[Philip Rhoades]

People,

I get an error trying to ssh from a BasicLinux floppy booted 486 (I want 
to sort out HD problems on the old Adaptec 1542 controlled SCSI drive 
that has RH5.2 on it!) when trying to connect to my Fedora 25 x86_64 
workstation.  On the F25 machine in /var/log/secure I get lines like:

Mar 13 16:25:47 phil sshd[7562]: Unable to negotiate with 192.168.1.40 
port 1034: no matching key exchange method found. Their offer: 
diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1 [preauth]

On the BasLin terminal I get:

OpenSSH_3.5p1, SSH protocols 1.5/2.0, OpenSSL 0x0090607f
debug1: Rhosts Authentication disabled, originating port will not be 
trusted.
debug1: ssh_connect: needpriv 0
debug1: Connecting to 192.168.1.20 [192.168.1.20] port 22.
debug1: Connection established.
debug1: identity file /root/.ssh/identity type -1
debug1: identity file /root/.ssh/id_rsa type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.3
debug1: match: OpenSSH_7.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.5p1
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: 
diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: 
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,[e-mail]
debug2: kex_parse_kexinit: 
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,[e-mail]
debug2: kex_parse_kexinit: 
hmac-md5,hmac-sha1,hmac-ripemd160,[e-mail],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: 
hmac-md5,hmac-sha1,hmac-ripemd160,[e-mail],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit: none,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: 
[e-mail],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha51
2,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1
debug2: kex_parse_kexinit: 
ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: kex_parse_kexinit: 
[e-mail],aes128-ctr,aes192-ctr,aes256-ctr,[e-mail],[e-mail]
debug2: kex_parse_kexinit: 
[e-mail],aes128-ctr,aes192-ctr,aes256-ctr,[e-mail],[e-mail]
debug2: kex_parse_kexinit: 
[e-mail],[e-mail],[e-mail],[e-mail],[e-mail],umac-64@openssh.
com,[e-mail],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: kex_parse_kexinit: 
[e-mail],[e-mail],[e-mail],[e-mail],[e-mail],[e-mail],[e-mail],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: kex_parse_kexinit: none,[e-mail]
debug2: kex_parse_kexinit: none,[e-mail]
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
no matching cipher found: client 
aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc,[e-mail] 
server 
[e-mail],aes128-ctr,aes192-ctr,aes256-ctr,[e-mail],[e-mail]
debug1: Calling cleanup 0x805deb0(0x0)

Any suggestions about how to fix this SSH problem?

Thanks,

Phil.

[Jakub Jelen]

On 03/13/2017 07:02 AM, Philip Rhoades wrote:
> People,
>
> I get an error trying to ssh from a BasicLinux floppy booted 486 (I want
> to sort out HD problems on the old Adaptec 1542 controlled SCSI drive
> that has RH5.2 on it!) when trying to connect to my Fedora 25 x86_64
> workstation.  On the F25 machine in /var/log/secure I get lines like:
>
> Mar 13 16:25:47 phil sshd[7562]: Unable to negotiate with 192.168.1.40
> port 1034: no matching key exchange method found. Their offer:
> diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1 [preauth]

You are connecting from very old OpenSSH client (3.5), which does not 
support any of the currently secure cryptography algorithms. You should 
really consider updating that BasicLinux.

Otherwise you can enable the legacy kex and ciphers in the Fedora 
OpenSSH server by following these instructions:

http://www.openssh.com/legacy.html

Regards,