VPN Setup

When devices are on different subnets (common with VPNs), mDNS discovery won’t work across subnets. Connecto provides a simple solution: save the remote subnet once, and scans will include it automatically.

The problem

┌─────────────────────────────────────────────────────────────┐
│                         VPN Network                          │
├─────────────────────────┬───────────────────────────────────┤
│   Subnet A: 10.0.1.0/24 │   Subnet B: 10.0.2.0/24          │
│                         │                                   │
│   ┌─────────────┐       │       ┌─────────────┐            │
│   │   Your Mac  │       │       │   Windows   │            │
│   │  10.0.1.50  │  ✗ mDNS ✗     │  10.0.2.100 │            │
│   └─────────────┘       │       └─────────────┘            │
│                         │                                   │
└─────────────────────────┴───────────────────────────────────┘

mDNS broadcasts don’t cross subnet boundaries, so connecto scan won’t find devices on other subnets.

The solution

Step 1: Find the remote subnet

Ask your colleague or check your VPN documentation for the subnet. Common formats:

• 10.0.2.0/24 (256 addresses)
• 192.168.100.0/24
• 172.16.5.0/24

Step 2: Save the Subnet

connecto config add-subnet 10.0.2.0/24

You can add multiple subnets:

connecto config add-subnet 10.0.3.0/24
connecto config add-subnet 192.168.100.0/24

Step 3: Scan and Pair

Now connecto scan will automatically include saved subnets:

connecto scan

  CONNECTO SCANNER

→ Scanning for devices...

✓ Found 1 device(s):

[0] windows-workstation (10.0.2.100:8099)

Pair as usual:

connecto pair 0

Managing subnets

List saved subnets

connecto config list

Configured subnets:
  • 10.0.2.0/24
  • 10.0.3.0/24

Remove a subnet

connecto config remove-subnet 10.0.3.0/24

Config file location

connecto config path

The config file is stored at:

• macOS/Linux: ~/.config/connecto/config.json
• Windows: %APPDATA%\connecto\config.json

One-time subnet scan

If you don’t want to save a subnet permanently, use the --subnet flag:

connecto scan --subnet 10.0.2.0/24

You can specify multiple subnets:

connecto scan -s 10.0.2.0/24 -s 10.0.3.0/24

Listener VPN hint

When someone pairs from a different subnet, the listener shows a helpful message:

✓ Successfully paired with mac-laptop!
  → They can now SSH to this machine.

VPN/Cross-subnet connection detected!
  → Tell mac-laptop to save your subnet for future scans:
    connecto config add-subnet 10.0.1.0/24

Direct pairing

If you know the exact IP, skip scanning entirely:

connecto pair 10.0.2.100:8099

Troubleshooting

Scan takes too long

Scanning large subnets can take time. Connecto scans up to 100 IPs concurrently with 500ms timeout per IP.

For faster scans, use a smaller subnet if possible:

• /24 = 254 IPs (~2-3 seconds)
• /22 = 1022 IPs (~5-10 seconds)
• /16 = 65534 IPs (not recommended)

Connection refused

Ensure:

1. The target is running connecto listen
2. Firewall allows TCP 8099
3. VPN is connected and routing works

Test connectivity:

# Check if port is open
nc -zv 10.0.2.100 8099