How to fix slow network using SSH to Linux Ubuntu on LAN network

Optimizing SSH on Ubuntu for Faster LAN Connection

At times, connecting to a remote Ubuntu machine via SSH can be slow and frustrating, especially when the connection is made over a local area network (LAN). Slow SSH connections can result from a variety of issues, ranging from high network latency to poorly configured server settings. In this guide, we will explore various ways to optimize SSH on Ubuntu for faster LAN connections.

Check Your Network

Before attempting to optimize SSH on Ubuntu, it is important to ensure that your network is functioning properly. Issues such as high network latency, packet loss, and network congestion can result in slow SSH connections. To diagnose network issues, use tools such as ping and traceroute to test network connectivity and measure latency.

DNS on local network can impact SSH connection:

vim /etc/ssh/sshd_config
# find and edit/add line:
UseDNS no

Powersave enabled on WIFI could also impact SSH speed:

sudo vim /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf
#change 3 to 2

How to speed up ssh connection – Use SSH Multiplexing

SSH multiplexing is a technique that allows you to reuse existing SSH connections for subsequent SSH sessions, thereby reducing the time it takes to establish a new connection. To enable SSH multiplexing, edit your SSH configuration file by adding the following lines:

Host *
ControlMaster auto
ControlPath ~/.ssh/sockets/%r@%h-%p
ControlPersist 600

At times, connecting to a remote Ubuntu machine via SSH can be slow and frustrating, especially when the connection is made over a local area network (LAN). Slow SSH connections can result from a variety of issues, ranging from high network latency to poorly configured server settings. In this guide, we will explore various ways to optimize SSH on Ubuntu for faster LAN connections.

Adjust SSH Cipher Settings

SSH encryption can also contribute to slow SSH connections, especially when the encryption algorithms are computationally expensive. To optimize SSH encryption settings, edit your SSH configuration file by adding the following lines:

Host *
Ciphers aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr
MACs hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha2-512

Use Compression

SSH compression can help to reduce the amount of data that is transmitted over the network, thereby improving SSH performance. To enable SSH compression, edit your SSH configuration file by adding the following lines:

Host *
Compression yes

Optimize Server Settings

Finally, optimizing server settings can also help to improve SSH performance. Some server settings that can be adjusted to optimize SSH performance include MaxSessions, MaxStartups, and TCPKeepAlive. Adjust these settings based on your specific server configuration and requirements.

Conclusion

In this guide, we have explored various ways to optimize SSH on Ubuntu for faster LAN connections. By checking your network, using SSH multiplexing, adjusting SSH cipher settings, using compression, and optimizing server settings, you can improve SSH performance and enjoy faster and more reliable SSH connections.