port 22

Linux: Block Port With IPtables

by Vivek Gite on December 10, 2010 · 5 comments

How do I block port number with iptables under Linux operating systems?

OpenSSH Hide Version Number From Clients

by Vivek Gite on September 13, 2010 · 0 comments

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

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?

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CentOS SSH Installation And Configuration

by Vivek Gite on March 14, 2009 · 3 comments

How do I install and configure ssh server and client under CentOS Linux operating systems?

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Monit: Monitor SSHD Server and Auto Restart SSH If It Does Not Respond

by Vivek Gite on March 13, 2008 · 5 comments

Q. How do I monitor my ssh server with monit? How do I restart ssh server if it does not respond or dead due to any issues under Linux?

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Iptables is not sending LOG to syslog file

by Vivek Gite on July 30, 2006 · 1 comment

Q. I am running SSH/MySQL/Webserver and setup iptables based firewall. But my logs are send to console rather than the system log files. How do make sure that iptables LOG target messages are send to /var/log/messages file? A. IPTABLES LOG module turns on kernel logging of matching packets. When this option is set for a [...]

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Restrict ssh access using tcpd (TCPWrapper)

by Vivek Gite on January 31, 2006 · 2 comments

tcpd is use to access control facility for internet services. The tcpd program can be set up to monitor incoming requests for telnet, finger, ftp, exec, rsh, rlogin, tftp, sshd and other services that have a one-to-one mapping onto executable files. Your sshd server must be configuring (compiled with) to support tcpd. You can find [...]

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Restrict ssh access using Iptable

by Vivek Gite on January 31, 2006 · 1 comment

Q. How do I stop or restrict access to my OpenSSH (SSHD) server using Linux iptables based firewall? A. Linux iptables firewall can be use to block or restrict access to ssh server. Iptables command is used to set up, maintain, and inspect the tables of IP packet filter rules in the Linux kernel. However, [...]

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