Hello, I have set up my router (WR940N) and connected one of the LAN ports to the WAN ports of my ISP router because my ISP's router has a phone port and I need it to make the phone functional. Although it does work, receive and send calls, it randomly hangs up after like 3-5 minutes. I've red.. Setting up NAT to forward traffic on port 21 to the internal server. Vigor Router supports FTP ALG (Application Layer Gateway), after open the FTP command port (TCP 21), the router will inspect the command packets to learn which port the FTP client will use for data transmitting, and then open the data port accordingly.
![[端口转发] FTP 服务器设置指南情境二 官方支持 ASUS 中国](https://kmpic.asus.com/images/2018/10/25/e410556d-c338-418c-a0c8-f762f02b5824.png "[端口转发] FTP 服务器设置指南情境二 官方支持 ASUS 中国")
![[端口转发] FTP 服务器设置指南情境一 官方支持 ASUS 中国](https://kmpic.asus.com/images/2018/11/01/e297181f-ed94-4c65-9738-1496564e87db.jpg "[端口转发] FTP 服务器设置指南情境一 官方支持 ASUS 中国")
![DLink DFL860E [256/552] The ftp alg chapter 6 security mechanisms](https://mcgrp.ru/views2/1018576/page256/bg100.png "DLink DFL860E [256/552] The ftp alg chapter 6 security mechanisms")
![[Wireless Router] How to set up Virtual Server/Port Forwarding Rules](https://kmpic.asus.com/images/2018/11/01/24f199b2-c8ad-4af6-8497-b03a93cc68a1.jpg "[Wireless Router] How to set up Virtual Server/Port Forwarding Rules on")
![[無線路由器][通訊埠轉發]設定FTP操作步驟情境三 官方支援 ASUS 台灣](https://kmpic.asus.com/images/2018/10/25/8a91ce7c-b5b7-47ab-b85c-0b09c5f834d5.jpg "[無線路由器][通訊埠轉發]設定FTP操作步驟情境三 官方支援 ASUS 台灣")
I was looking for ways to harden the security on my TP-Link router and found the ALG (Application Layer Gateway) settings under the security section. I have disabled the following: PPTP Pass-throug.. The FTP client is getting a so called passive data port assigned, the FTP ALG does take care of the port forwarding. This is absolutely normal on any NAT router.