On Mon, Jan 13, 2020 at 01:00:05PM -0500, Stephen John Smoogen wrote:
> On Mon, 13 Jan 2020 at 12:23, Patrick Bégou
> <Patrick.Begou@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Hi,
> >
> > I have a strange problem with a freshly installed Centos7 desktop
> > (most8pc25). I can't ssh to 2 CentOS6 servers, even with firewall
> > disabled on the client and on the server. But I can connect from the
> > server to the client, all in the same VLAN. I can also ssh from this
> > desktop to centos7 servers in the same VLAN or in another VLAN.
> >
> > No idea about this problem.
> >
> > On the server kareline (client is most8pc25), tcpdump says:
> >
>
> So the client is able to talk to the server and the server is responding.
>
> >
> > On the Centos7 client, with "-v -v" ssh says:
> >
> >
> > [tec21@most8pc25 ~]$ssh -v -v kareline
> > OpenSSH_7.4p1, OpenSSL 1.0.2k-fips 26 Jan 2017
> > debug1: Reading configuration data /etc/ssh/ssh_config
> > debug1: /etc/ssh/ssh_config line 58: Applying options for *
> > debug1: Connecting to kareline [194.254.66.8] port 22.
> > debug1: Connection established.
>
> ^^ this says the first part started working.
>
>
> > debug1: Local version string SSH-2.0-OpenSSH_7.4
> > debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
> > debug1: match: OpenSSH_5.3 pat OpenSSH_5* compat 0x0c000000
> > debug1: Authenticating to kareline:22 as 'tec21'
> > debug1: SSH2_MSG_KEXINIT sent
> > debug1: SSH2_MSG_KEXINIT received
>
> It got items and says it is going to use the user tec21 to login
>
> > debug2: local client KEXINIT proposal
>
> > debug1: kex: client->server cipher: aes128-ctr MAC: umac-64@xxxxxxxxxxx
> > debug1: kex: diffie-hellman-group-exchange-sha256 need=16 dh_need=16
> > debug1: kex: diffie-hellman-group-exchange-sha256 need=16 dh_need=16
> > debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<3072<8192) sent
> > Connection closed by 194.254.66.8 port 22
> >
>
> The server then stops the connection. I would then go through the
> following on the host:
> 1. Is fail2ban or something else dropping the connection for some reason?
> 2. Is there a log in /var/log/secure to say something is going on?
> 3. Does running the server on port 2222 in debug mode and connecting
> from the client give a reason for it dieing?
> 4. On the client and server are /etc/ssh/*_config changed from
> defaults and what changes are there. Sometimes saying you want XYZ
> algo in one and not having it in another causes dropped connections
> but I thought it gave an error.
How about selinux on the remotes?
Fred
--
---- Fred Smith -- fredex@xxxxxxxxxxxxxxxxxxxxxx -----------------------------
"For the word of God is living and active. Sharper than any double-edged
sword, it penetrates even to dividing soul and spirit, joints and marrow;
it judges the thoughts and attitudes of the heart."
---------------------------- Hebrews 4:12 (niv) ------------------------------
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