When attempting direct SSH access to a Vagrant VM (IP: 10.0.0.23, hostname: lamp-vm) using ssh vagrant@lamp-vm, we encounter a connection timeout on port 22 despite successful vagrant ssh connections.

First, verify the VM's network interface configuration. Run this inside the VM:

vagrant ssh -c "ip addr show | grep 'inet '"

Compare the output with your local /etc/hosts entry (10.0.0.23 lamp-vm). The private network interface should appear as:

inet 10.0.0.23/24 brd 10.0.0.255 scope global eth1

Check if SSH is actually running on the expected port:

vagrant ssh -c "sudo netstat -tulpn | grep sshd"

Expected output:

tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1234/sshd

Inspect iptables rules that might block external SSH access:

vagrant ssh -c "sudo iptables -L -n -v"

Look for any DROP/REJECT rules targeting port 22 from external sources.

Your Vagrantfile should explicitly configure the private network:

config.vm.network "private_network", ip: "10.0.0.23"
config.vm.network "forwarded_port", guest: 22, host: 2222, id: "ssh"

Try these SSH command variations:

ssh -vvv -o IdentitiesOnly=yes -i ~/.vagrant.d/insecure_private_key vagrant@10.0.0.23

Or using the forwarded port:

ssh -p 2222 vagrant@127.0.0.1

Update your ~/.ssh/config with more specific parameters:

Host lamp-vm
  HostName 10.0.0.23
  User vagrant
  IdentityFile ~/.ssh/vagrant
  IdentitiesOnly yes
  StrictHostKeyChecking no
  UserKnownHostsFile /dev/null
  LogLevel DEBUG3

Ensure proper permissions for SSH keys:

chmod 700 ~/.ssh
chmod 600 ~/.ssh/vagrant
chmod 644 ~/.ssh/config

Run these local network tests:

ping -c 4 10.0.0.23
nc -zv 10.0.0.23 22
traceroute 10.0.0.23

Understand how Vagrant manages SSH connections:

vagrant ssh-config

This reveals the actual connection parameters Vagrant uses, including the exact private key path and any port forwarding in effect.

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When working with Vagrant VMs, direct SSH access might fail even when vagrant ssh works perfectly. The error message:

debug1: connect to address 10.0.0.23 port 22: Connection timed out
ssh: connect to host lamp-vm port 22: Connection timed out

typically indicates network-level connectivity issues rather than authentication problems.

First verify your VM's network settings in the Vagrantfile:

config.vm.network "private_network", ip: "10.0.0.23"

Then confirm the interface is up:

# On host machine
ping 10.0.0.23

# Inside VM (via vagrant ssh)
ip addr show

Vagrant VMs often have restrictive firewall rules. Check these common solutions:

# Ubuntu/Debian VM
sudo ufw allow 22/tcp

# CentOS/RHEL VM
sudo firewall-cmd --add-service=ssh --permanent
sudo firewall-cmd --reload

Your ~/.ssh/config appears correct, but let's enhance it:

Host lamp-vm
    HostName 10.0.0.23
    User vagrant
    IdentityFile ~/.ssh/vagrant
    Port 22
    TCPKeepAlive yes
    ServerAliveInterval 60

Vagrant uses its own key pairs. To use them directly:

ssh -i ~/.vagrant.d/insecure_private_key vagrant@10.0.0.23

Or for newer versions:

ssh -i /path/to/your/vagrant_project/.vagrant/machines/default/virtualbox/private_key vagrant@10.0.0.23

If direct connection fails, set up port forwarding in Vagrantfile:

config.vm.network "forwarded_port", 
    guest: 22,
    host: 2222,
    id: "ssh",
    auto_correct: true

Then connect via:

ssh -p 2222 vagrant@localhost

Always use verbose SSH flags for troubleshooting:

ssh -vvv vagrant@lamp-vm

This reveals exactly where the connection fails in the TCP handshake.