Notes on setting up a Sakura VPS as an SSH SOCKS proxy because I needed a fixed IP address.

When testing connectivity in an environment that has IP restrictions, you may want to allow only your own source IP as an exception.

However, the global IP address of your home connection isn’t static; it changes whenever you restart the router or for other reasons.

Updating the allowed IP each time is cumbersome, so I use a Sakura VPS as a jump host.

I could have set up IPsec with something like SoftEther VPN, but since SSH is available, using a SOCKS proxy is easier if everything can be done on the local PC.

Goal

The setup looks like this.

Firefox
  ↓
localhost:1080
  ↓
SSH
  ↓
Sakura VPS
  ↓
Internet

Creating a SOCKS proxy with SSH

Use SSH’s dynamic port forwarding.

In this case, we’ll configure port 1080.

ssh -D 1080 Bastion

Bastion is the VPS registered under ~/.ssh/config.

Configure it as follows.

Host Bastion
    HostName xxx.xxx.xxx.xxx
    User username
    IdentityFile ~/.ssh/id_ed25519

While the SSH connection is active,

127.0.0.1:1080

becomes the endpoint and listens as a SOCKS proxy.

Verifying that it’s listening

On macOS you can check it with lsof.

lsof -iTCP:1080 -sTCP:LISTEN

For example,

COMMAND   PID   USER   FD   TYPE   NAME
ssh       ...   ...    ...  TCP    localhost:socks (LISTEN)

will be displayed.

Verifying that the traffic goes through the VPS with curl

Check with curl before configuring Firefox.

curl --proxy socks5h://127.0.0.1:1080 https://ifconfig.me

If the displayed IP is the Sakura VPS’s global IP, the setup is successful.

Using socks5h also causes hostname resolution to be performed on the SOCKS proxy side.

Routing only Firefox through the SOCKS proxy

In this case we didn’t need to route the entire Mac through the VPS, so we only configure Firefox—the browser used for connectivity testing—to use the proxy.
In fact, having separate browsers for Chrome and Firefox, each with and without IP restrictions, is convenient, which is why we set it up this way.

Open Firefox’s

Settings
↓
General
↓
Network settings
↓
Connection settings

and select “Manual proxy configuration.”

SOCKS Host:

127.0.0.1

Port:

1080

Select the SOCKS version:

SOCKS v5

Also enable

When using SOCKS v5, also use a proxy for DNS

Now only Firefox’s traffic will be routed through the VPS.

Using it for IP‑restriction connectivity testing

For example, if a service restricts connections by source IP like

Allowed IPs:
xxx.xxx.xxx.xxx/32

register the Sakura VPS’s IP address in that list.

Accessing from your home network normally will be denied.

When Firefox is configured to go through the SSH SOCKS proxy,

Firefox
↓
SSH SOCKS
↓
Sakura VPS
↓
IP‑restricted services

the service will see the connection as coming from the VPS’s IP.