SSH Keys

Using SSH keys to access your server provides more security than using the standard username and password combination. To set up your SSH Keys, use the following steps:

1. On your local machine create the public/private key combination. The private key you will keep, and the matching public key is copied to the server. Setting a passphrase here is optional, if you set one you will always be prompted for it when logging in.

# Generate SSH Keys
user@ubuntu:~$ ssh-keygen -t rsa

Generating public/private rsa key pair.
Enter file in which to save the key (/home/user/.ssh/id_rsa):
Created directory '/home/user/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/user/.ssh/id_rsa.
Your public key has been saved in /home/user/.ssh/id_rsa.pub.
The key fingerprint is:
02:82:38:95:e5:30:d2:ad:17:60:15:7f:94:17:9f:30 user@ubuntu
The key\'s randomart image is:
+--[ RSA 2048]----+

2. SFTP to your server, and copy the public key to the ~/.ssh folder.

# SFTP to your server
$ sftp user@hostname

# copy your public key
sftp> mput /home/user/.ssh/id_rsa.pub /home/user/.ssh
Uploading /home/user/.ssh/id_rsa.pub to /home/user/.ssh/id_rsa.pub
/home/user/.ssh/id_rsa.pub      100%  394     0.4KB/s   00:00

3. On your server, add the public key to the :file:`~/.ssh/authorized_keys` file.

$ cat /home/user/.ssh/id_rsa.pub > /home/user/.ssh/authorized_keys

You should now be able to log into your server using your SSH Keys. If you've added a passphrase you'll be asked for it. For more information about using SSH keys with |RCE| |repos|, see the :ref:`ssh-connection` section.

VPN Whitelist

Most company networks will have a VPN. If you need to set one up, there are many tutorials online for how to do that. Getting it right requires good knowledge and attention to detail. Once set up, you can configure your |RCE| instances to only allow user access from the VPN, to do this see the :ref:`settip-ip-white` section.

Public Key Infrastructure and SSL/TLS Encryption

Public key infrastructure (PKI) is a system that creates, manages, and validates certificates for identifying nodes on a network and encrypting communication between them. SSL or TLS certificates can be used to authenticate different entities with one another. To read more about PKIs, see the OpenSSL PKI tutorial site, or this Cloudflare PKI post.

If the network you are running is SSL/TLS encrypted, you can configure |RCE| to always use secure connections using the force_https and use_htsts options in the :file:`/home/user/.rccontrol/instance-id/rhodecode.ini` file. For more details, see the :ref:`x-frame` section.

FireWalls and Ports

Setting up a network firewall for your internal traffic is a good way of keeping it secure by blocking off any ports that should not be used. Additionally, you can set non-default ports for certain functions which adds an extra layer of security to your setup.

A well configured firewall will restrict access to everything except the services you need to remain open. By exposing fewer services you reduce the number of potential vulnerabilities.

There are a number of different firewall solutions, but for most Linux systems using the built in IpTables firewall should suffice. On BSD systems you can use IPFILTER or IPFW. Use the following examples, and the IpTables documentation to configure your IP Tables on Ubuntu.

Changing the default SSH port.

# Open SSH config file and change to port 10022
vi /etc/ssh/sshd_config

# What ports, IPs and protocols we listen for
Port 10022

Setting IP Table rules for SSH traffic. It is important to note that the default policy of your IpTables can differ and it is worth checking how each is configured. The options are ACCEPT, REJECT, DROP, or LOG. The usual practice is to block access on all ports and then enable access only on the ports you with to expose.

# Check iptables policy
$ sudo iptables -L

Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

# Close all ports by default
$ sudo iptables -P INPUT DROP

$ sudo iptables -L
Chain INPUT (policy DROP)
target     prot opt source               destination
DROP       all  --  anywhere             anywhere

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

# Deny outbound SSH traffic
sudo iptables -A OUTPUT -p tcp --dport 10022 -j DROP

# Allow incoming SSH traffic on port 10022
sudo iptables -A INPUT -p tcp --dport 10022 -j ACCEPT

# Allow incoming HTML traffic on port 80 and 443
iptables -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --dport 443 -j ACCEPT

Saving your IP Table rules, and restoring them from file.

# Save you IP Table Rules
iptables-save

# Save your IP Table Rules to a file
sudo sh -c "iptables-save > /etc/iptables.rules"

# Restore your IP Table rules from file
iptables-restore < /etc/iptables.rules