fix: docker-windows-vm의 iptables 오류 수정

docker/docker-windows-vm/startup.sh

@@ -43,19 +43,27 @@ fi
 
 echo "Windows VM IP Address: $VM_IP"
 
-# On the Docker HOST, add a rule to the DOCKER-USER chain to allow
-# incoming RDP traffic to be forwarded to the container.
-# This is the correct way to allow traffic when the FORWARD policy is DROP.
-echo "Allowing RDP forwarding on the Docker host..."
-iptables -I DOCKER-USER -p tcp --dport 33890 -j ACCEPT
-
-# Inside the container, configure iptables for RDP port forwarding to the VM
-echo "Configuring iptables for RDP..."
+# Enable IP forwarding and configure NAT
+echo "Enabling IP forwarding and NAT for RDP..."
+sysctl -w net.ipv4.ip_forward=1
+
+# iptables에 필요한 커널 모듈 로드
+echo "Loading required kernel modules for iptables..."
+modprobe ip_tables
+modprobe iptable_nat
+modprobe nf_nat
+modprobe xt_conntrack
+
 iptables -t nat -A PREROUTING -p tcp --dport 3389 -j DNAT --to-destination "$VM_IP":3389
 iptables -t nat -A POSTROUTING -j MASQUERADE
 
-echo "Port forwarding rule added."
-echo "RDP connections to this container on port 3389 will be forwarded to the Windows VM."
+# Configure RDP forwarding inside the container
+echo "Allowing RDP forwarding to the VM..."
+iptables -I FORWARD -d "$VM_IP" -p tcp --dport 3389 -j ACCEPT
+iptables -I FORWARD -s "$VM_IP" -j ACCEPT
+
+# Keep the container running to maintain the VM session
+echo "Windows VM is running. You can connect via RDP at $VM_IP."
 
 # Keep the container running
 echo "Container is running. Use 'docker exec' to access it."