OpenSSH Hide Version Number From Clients

Posted on in Categories last updated September 13, 2010

How do I hide ssh number from clients? When I type the following command it displays server version number to end users:

ssh -v server2.example.com

OpenSSH_5.3p1 Debian-3ubuntu4, OpenSSL 0.9.8k 25 Mar 2009
debug1: Reading configuration data /home/vivek/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to server2.example.com [123.x.y.z] port 22.
debug1: Connection established.
debug1: identity file /home/vivek/.ssh/identity type -1
debug1: identity file /home/vivek/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /home/vivek/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3
debug1: match: OpenSSH_4.3 pat OpenSSH_4*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.3p1 Debian-3ubuntu4

OR

telnet server2.example.com 22
Trying 123.x.y.z...
Connected to v.txvip1.
Escape character is '^]'.
SSH-2.0-OpenSSH_4.3

Why does OpenSSH server report its version to clients?

How do I Load / Start RHEL / CentOS / Fedora Linux Iptables Firewall on Computer Boot?

Posted on in Categories , , , , , , last updated January 29, 2008

Q. I’d like to start my Iptables based firewall when my computer comes online so that it get protected from the Internet? I’m using CentOS Linux Server version 4.x.

A. CentOS / RHEL / Fedora Linux has service located at /etc/init.d/iptables to start firewall on boot. All you have to do is type the following command to turn on firewall on boot:
# chkconfig iptables on

Your firewall rules are saved at /etc/sysconfig/iptables files.