To verify your running OpenSSH version on FreeBSD 8.1, execute either of these commands:

# Method 1: Using ssh -V
ssh -V 2>&1 | awk '{print $1,$2}'

# Method 2: Checking the package info
pkg info | grep -i openssh

# Method 3: Querying the running daemon (requires root)
sockstat -4l | grep sshd
/usr/sbin/sshd -V | head -1

Before upgrading, take these essential precautions:

• Backup your sshd_config: cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak
• Check for active connections: netstat -an | grep :22
• Document custom PAM settings if applicable

The recommended approach for FreeBSD 8.1:

# Update package database
pkg_update

# Upgrade OpenSSH package
pkg_upgrade -r openssh-portable

# Alternatively, force reinstallation
pkg_delete -f openssh-*
pkg_add -r openssh-portable

For specific version requirements:

# Fetch the source
fetch ftp://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-8.9p1.tar.gz
tar xzf openssh-*.tar.gz
cd openssh-*

# Configure and compile
./configure --prefix=/usr --with-pam --with-tcp-wrappers
make
make install

# Verify the new version
/usr/local/sbin/sshd -V

After installation:

1. Merge your old configuration: diff -u /etc/ssh/sshd_config.bak /etc/ssh/sshd_config
2. Restart the service: /etc/rc.d/sshd restart
3. Test connectivity: ssh -v localhost

Confirm successful upgrade:

ssh -V
ps aux | grep sshd | grep -v grep

For emergency rollback:

pkg_add -f /var/db/pkg/openssh-*.tbz
cp /etc/ssh/sshd_config.bak /etc/ssh/sshd_config

To verify the installed OpenSSH version on FreeBSD 8.1, execute either of these commands in terminal:

ssh -V
# Sample output: OpenSSH_5.8p1, OpenSSL 0.9.8q 2 Dec 2010

or

pkg info | grep openssh
# Output shows package name with version string

For systems using binary packages:

sudo pkg upgrade openssh-portable
sudo service sshd restart

Note: FreeBSD 8.1 uses legacy package tools. Modern systems would use pkg instead of pkg_add.

For custom builds or security patches:

# Fetch ports tree if unavailable
sudo portsnap fetch extract

# Navigate to SSH port
cd /usr/ports/security/openssh

# Configure and install
sudo make config-recursive
sudo make install clean

# Verify new version
sshd -v

After upgrade:

# Backup original config
sudo cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak

# Merge custom configurations
sudo service sshd restart

If encountering libcrypto errors:

# Reinstall dependencies
sudo pkg install -f openssl

Check compatibility with:

ldd $(which sshd)