Wire IPAuth into your server.

Save the update script

Drop this at /usr/local/bin/ipauth-update.sh. The SERVER_URL below carries your server key; change PORT if you're not gating SSH. The state file at /var/cache/ipauth-last tracks the last IP we added so we can delete it cleanly. Your firewall never accumulates stale entries.

#!/bin/sh
SERVER_URL="https://ipauth.net/serverquery/?key=YOUR_SERVER_KEY"
PORT=22
STATE=/var/cache/ipauth-last

CURIP=$(curl --max-time 5 -fsS "$SERVER_URL" | grep -oE '"ipaddress":"[0-9.]+' | cut -d'"' -f4)
[ -z "$CURIP" ] && exit 0

OLDIP=$(cat "$STATE" 2>/dev/null)
[ "$CURIP" = "$OLDIP" ] && exit 0   # unchanged → no-op

# Remove the previous allow (if any), then add the current one.
[ -n "$OLDIP" ] && ufw delete allow from "$OLDIP" to any port "$PORT" proto tcp >/dev/null 2>&1
ufw allow from "$CURIP" to any port "$PORT" proto tcp comment "ipauth"
echo "$CURIP" > "$STATE"

sudo chmod +x /usr/local/bin/ipauth-update.sh

Schedule it (every 2 minutes)

sudo crontab -e →

*/2 * * * * /usr/local/bin/ipauth-update.sh

Verify

Click your auth URL, wait 2 min, then check:

sudo ufw status | grep ipauth

Save the update script

Save as /usr/local/bin/ipauth-update.sh:

#!/bin/sh
SERVER_URL="https://ipauth.net/serverquery/?key=YOUR_SERVER_KEY"
PORT=22
COMMENT="ipauth"

CURIP=$(curl --max-time 5 -fsS "$SERVER_URL" | grep -oE '"ipaddress":"[0-9.]+' | cut -d'"' -f4)
[ -z "$CURIP" ] && exit 0

# Remove any prior ipauth allow rules for this port, then add fresh.
iptables -S INPUT | grep -- "--comment \"$COMMENT\"" | sed 's/^-A /-D /' | while read R; do
    iptables $R 2>/dev/null
done
iptables -I INPUT -p tcp --dport "$PORT" -s "$CURIP" -m comment --comment "$COMMENT" -j ACCEPT

sudo chmod +x /usr/local/bin/ipauth-update.sh

Schedule it

*/2 * * * * /usr/local/bin/ipauth-update.sh

If you use iptables-persistent, also run netfilter-persistent save after the rule lands, OR add a second cron entry to do it.

Verify

sudo iptables -L INPUT -n --line-numbers | grep ipauth

Save the update script

Save as C:\Scripts\ipauth-update.ps1:

# ipauth-update.ps1
$ServerUrl = "https://ipauth.net/serverquery/?key=YOUR_SERVER_KEY"
$Port      = 22
$RuleName  = "IPAuth-Allow-$Port"

try {
    $resp = Invoke-RestMethod -Uri $ServerUrl -TimeoutSec 5
    if (-not $resp.ipaddress) { exit 0 }
    $ip = $resp.ipaddress
} catch { exit 0 }

Get-NetFirewallRule -DisplayName $RuleName -ErrorAction SilentlyContinue | Remove-NetFirewallRule
New-NetFirewallRule -DisplayName $RuleName `
    -Direction Inbound -Action Allow `
    -Protocol TCP -LocalPort $Port `
    -RemoteAddress $ip `
    -Profile Any | Out-Null

Schedule it (every 2 minutes)

$action  = New-ScheduledTaskAction -Execute "powershell.exe" `
    -Argument "-NoProfile -ExecutionPolicy Bypass -File C:\Scripts\ipauth-update.ps1"
$trigger = New-ScheduledTaskTrigger -Once -At (Get-Date) `
    -RepetitionInterval (New-TimeSpan -Minutes 2) `
    -RepetitionDuration (New-TimeSpan -Days 3650)
$principal = New-ScheduledTaskPrincipal -UserId "SYSTEM" -RunLevel Highest

Register-ScheduledTask -TaskName "IPAuth-Update" `
    -Action $action -Trigger $trigger -Principal $principal `
    -Description "Updates Windows Firewall rule from IPAuth"

Verify

Get-NetFirewallRule -DisplayName "IPAuth-Allow-*" |
    Get-NetFirewallAddressFilter |
    Select-Object RemoteAddress

Alternative: register on PowerShell startup (laptop / workstation pattern)

If you're using IPAuth from a Windows laptop (not a server), you probably want it to register your IP every time you open PowerShell. So new SSH sessions to your remote boxes work immediately after a network change. This is what we use ourselves.

Open your $PROFILE:

notepad $PROFILE
# (if the file doesn't exist yet, PowerShell will offer to create it)

Add a $Servers hash table and a startup loop that hits each auth URL (not server URL. This is the client-side click equivalent) and prints a status line:

$Servers = @{
    'webprod' = @{
        IPAuthAuth = 'https://ipauth.net/whitelist/?key=YOUR_AUTH_KEY_HERE'
        HealthURL  = 'https://web.example.com/'
    }
    # add more boxes as @{ IPAuthAuth = '...'; HealthURL = '...' }
}

try {
    $publicIP = Invoke-RestMethod 'https://api.ipify.org' -TimeoutSec 5
} catch { $publicIP = '(lookup failed)' }
Write-Host "Your public IP is: " -NoNewline
Write-Host $publicIP -ForegroundColor Cyan

$statusParts = @()
foreach ($name in $Servers.Keys | Sort-Object) {
    $cfg = $Servers[$name]
    try { Invoke-RestMethod $cfg.IPAuthAuth -TimeoutSec 5 | Out-Null; $ipauthOK = $true }
    catch { $ipauthOK = $false }
    try {
        $r = Invoke-WebRequest $cfg.HealthURL -UseBasicParsing -TimeoutSec 5 -ErrorAction Stop
        $healthOK = $r.StatusCode -eq 200
    } catch { $healthOK = $false }

    $color = if ($ipauthOK -and $healthOK) { 'Green' } elseif ($healthOK) { 'Yellow' } else { 'Red' }
    $state = if ($healthOK) { 'UP' } else { 'DOWN' }
    if (-not $ipauthOK) { $state += '(no-ipauth)' }
    $statusParts += @{ Name = $name; State = $state; Color = $color }
}
$first = $true
foreach ($p in $statusParts) {
    if (-not $first) { Write-Host " | " -NoNewline }
    Write-Host "$($p.Name): " -NoNewline
    Write-Host $p.State -ForegroundColor $p.Color -NoNewline
    $first = $false
}
Write-Host ""

Save and close. Every new PowerShell window now auto-registers your current IP with every server's IPAuth key in $Servers, prints your public IP, and shows a per-server up/down summary. If you switch networks (coffee shop → home), just open a new PS window and you're back in within the server's poll window.

Server side still needs the cron from steps 1-3 above. This client-side helper just clicks the auth URL for you. The two pieces work together.

Add an IPAuth anchor to pf

Edit /etc/pf.conf (sudo):

anchor "ipauth"
load anchor "ipauth" from "/etc/pf.anchors/ipauth"

Create /etc/pf.anchors/ipauth:

table <ipauth_allow> persist
pass in proto tcp from <ipauth_allow> to any port 22 keep state

Enable pf and load:

sudo pfctl -e
sudo pfctl -f /etc/pf.conf

Save the update script

Save as /usr/local/bin/ipauth-update.sh:

#!/bin/sh
SERVER_URL="https://ipauth.net/serverquery/?key=YOUR_SERVER_KEY"

CURIP=$(curl --max-time 5 -fsS "$SERVER_URL" | grep -oE '"ipaddress":"[0-9.]+' | cut -d'"' -f4)
[ -z "$CURIP" ] && exit 0

pfctl -a ipauth -t ipauth_allow -T replace "$CURIP" 2>/dev/null

sudo chmod +x /usr/local/bin/ipauth-update.sh

Schedule it (every 2 minutes via launchd)

Save as /Library/LaunchDaemons/net.ipauth.update.plist:

<?xml version="1.0" encoding="UTF-8"?>
<plist version="1.0">
<dict>
    <key>Label</key><string>net.ipauth.update</string>
    <key>ProgramArguments</key>
    <array><string>/usr/local/bin/ipauth-update.sh</string></array>
    <key>StartInterval</key><integer>120</integer>
    <key>RunAtLoad</key><true/>
</dict>
</plist>

sudo launchctl load -w /Library/LaunchDaemons/net.ipauth.update.plist

Verify

sudo pfctl -a ipauth -t ipauth_allow -T show

Declare the IPAuth table in pf.conf

Add to /etc/pf.conf:

table <ipauth_allow> persist
pass in on egress proto tcp from <ipauth_allow> to any port 22 keep state

doas pfctl -f /etc/pf.conf

Save the update script

#!/bin/sh
SERVER_URL="https://ipauth.net/serverquery/?key=YOUR_SERVER_KEY"

CURIP=$(ftp -V -M -o - "$SERVER_URL" 2>/dev/null | grep -oE '"ipaddress":"[0-9.]+' | cut -d'"' -f4)
[ -z "$CURIP" ] && exit 0

pfctl -t ipauth_allow -T replace "$CURIP" 2>/dev/null

doas chmod +x /usr/local/bin/ipauth-update.sh

Schedule it

Edit root's crontab via doas crontab -e:

*/2 * * * * /usr/local/bin/ipauth-update.sh

Verify

doas pfctl -t ipauth_allow -T show

Add the IPAuth rule

Append to /etc/ipfw.rules (or wherever your ruleset lives):

ipfw table 10 create type addr
ipfw add allow tcp from table\(10\) to any 22 in

Reload your ruleset (typically /etc/rc.d/ipfw restart).

Save the update script

#!/bin/sh
SERVER_URL="https://ipauth.net/serverquery/?key=YOUR_SERVER_KEY"

CURIP=$(fetch -q -T 5 -o - "$SERVER_URL" | grep -oE '"ipaddress":"[0-9.]+' | cut -d'"' -f4)
[ -z "$CURIP" ] && exit 0

# Replace table 10 contents with just the current IP.
ipfw table 10 flush
ipfw table 10 add "$CURIP"

chmod +x /usr/local/bin/ipauth-update.sh

Schedule it

Root's crontab:

*/2 * * * * /usr/local/bin/ipauth-update.sh

Verify

ipfw table 10 list