Port Forwarding

Lima supports automatic port-forwarding of localhost ports from guest to host.

Port forwarding types

Using SSH

SSH based port forwarding is the default and current model that is supported in Lima prior to v1.0.

To use SSH forwarding use the below command

LIMA_SSH_PORT_FORWARDER=true limactl start

Caveats

  • Doesn’t support UDP based port forwarding
  • Spans child process on host for running SSH master.

Using GRPC (Default since Lima v1.0)

Warning This mode is experimental

⚡ RequirementLima >= 1.0

In this model, lima uses existing GRPC communication (Host <-> Guest) to tunnel port forwarding requests. For each port forwarding request, a GRPC tunnel is created and this will be used for transmitting data

To disable this feature and use SSH forwarding use the following environment variable

LIMA_SSH_PORT_FORWARDER=true limactl start

Advantages

  • Supports both TCP and UDP based port forwarding
  • Performs faster compared to SSH based forwarding
  • No additional child process for port forwarding

Benchmarks

UsecaseGRPCSSH
TCP3.80 Gbits/sec3.38 Gbits/sec
TCP Reverse4.77 Gbits/sec3.08 Gbits/sec

The benchmarks detail above are obtained using the following commands

Host -> limactl start vz

VZ Guest -> iperf3 -s

Host -> iperf3 -c 127.0.0.1 //Benchmark for TCP 
Host -> iperf3 -c 127.0.0.1 -R //Benchmark for TCP Reverse
Last modified September 2, 2024: Revamp port forwarding to support UDP (13e9cbc)