Access LM Studio API running on Windows from another device (Mac) on the same network.

LM Studio Remote Access Setup (Windows → Mac).md

LM Studio Remote Access Setup (Windows → Mac)

Overview

Access LM Studio API running on Windows from another device (Mac) on the same network.

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1. Find Listening Ports (Windows PowerShell)

(Get-NetTCPConnection -State Listen | Select-Object -ExpandProperty LocalPort -Unique | Sort-Object) | ConvertTo-Json -Compress

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2. Check What's Using a Specific Port

Get-NetTCPConnection -LocalPort 15100 | Select-Object LocalAddress, LocalPort, State, @{Name='Process';Expression={(Get-Process -Id $_.OwningProcess).ProcessName}}

Good output: LocalAddress should be 0.0.0.0 (accepts all connections) Bad output: 127.0.0.1 (localhost only — reconfigure the app)

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3. Check Firewall Rules for a Port

Get-NetFirewallPortFilter | Where-Object { $_.LocalPort -eq 15100 } | Get-NetFirewallRule | Where-Object { $_.Enabled -eq 'True' } | Select-Object DisplayName, Direction, Action, Enabled | Format-Table -AutoSize

No output = no rule exists (inbound blocked by default).

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4. Create Firewall Rules (Allow Inbound + Outbound)

New-NetFirewallRule -DisplayName "Allow Port 15100 Inbound" -Direction Inbound -Protocol TCP -LocalPort 15100 -Action Allow; New-NetFirewallRule -DisplayName "Allow Port 15100 Outbound" -Direction Outbound -Protocol TCP -LocalPort 15100 -Action Allow

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5. Verify Firewall Rules Were Created

Get-NetFirewallPortFilter | Where-Object { $_.LocalPort -eq 15100 } | Get-NetFirewallRule | Select-Object DisplayName, Direction, Action, Enabled | Format-Table -AutoSize

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6. Remove Firewall Rules (If Needed)

Remove-NetFirewallRule -DisplayName "Allow Port 15100 Inbound"; Remove-NetFirewallRule -DisplayName "Allow Port 15100 Outbound"

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7. Find Windows Machine's Real IP

Get-NetIPAddress -AddressFamily IPv4 | Where-Object { $_.IPAddress -notlike "127.*" -and $_.IPAddress -notlike "169.*" } | Select-Object InterfaceAlias, IPAddress

Use the Wi-Fi or Ethernet IP (e.g., 192.168.2.177) Don't use: VirtualBox (192.168.56.x) or Hyper-V (172.x.x.x) IPs

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8. Test Connectivity From Mac

Test port is open:

nc -zv 192.168.2.177 15100

Test API responds:

curl --max-time 30 http://192.168.2.177:15100/v1/models

Test chat completion:

curl --max-time 300 http://192.168.2.177:15100/v1/chat/completions -H "Content-Type: application/json" -d '{"model": "qwen/qwen3-coder-30b", "messages": [{"role": "system", "content": "You answer only in rhymes."}, {"role": "user", "content": "What is your favorite color?"}]}'

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9. See All Listening Ports With Process Names

Get-NetTCPConnection -State Listen | Select-Object LocalPort, @{Name='PID';Expression={$_.OwningProcess}}, @{Name='Process';Expression={(Get-Process -Id $_.OwningProcess).ProcessName}}, @{Name='Path';Expression={(Get-Process -Id $_.OwningProcess).Path}} | Sort-Object LocalPort | Format-Table -AutoSize

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10. Check Firewall Status

Get-NetFirewallProfile | Select-Object Name, Enabled, DefaultInboundAction, DefaultOutboundAction | Format-Table -AutoSize

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11. List All Listening Ports (Alternative Methods)

Linux/macOS (zsh):

netstat -an 2>/dev/null | grep LISTEN | grep -oE ':\d+' | sed 's/://' | sort -nu | paste -sd, - | sed 's/^/[/;s/$/]/'

Windows (from CMD):

powershell -Command "(Get-NetTCPConnection -State Listen | Select-Object -ExpandProperty LocalPort -Unique | Sort-Object) | ConvertTo-Json -Compress"

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Troubleshooting

Symptom	Cause	Fix
nc times out	Wrong IP (VirtualBox/Hyper-V)	Use Wi-Fi/Ethernet IP
nc connection refused	Firewall blocking or service not running	Add firewall rule, check service
API hangs	Large model, slow inference	Wait longer, use smaller model
LocalAddress is 127.0.0.1	App only accepts localhost	Reconfigure app to bind to 0.0.0.0
PowerShell command freezes	Inefficient firewall query	Use Get-NetFirewallPortFilter first

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Common IPs to Ignore

IP Pattern	What It Is
192.168.56.x	VirtualBox Host-Only
172.x.x.x	Hyper-V / WSL
127.0.0.1	Localhost
169.254.x.x	APIPA (no network)

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Common Ports Reference

Port	Service
22	SSH
135, 139, 445	Windows Core (RPC, NetBIOS, SMB)
3389	Remote Desktop (RDP)
5800, 5900	VNC
5985, 47001	WinRM
9222	Chrome DevTools
15100	LM Studio (default)
27015	Steam