# Problem using printer on port 9100 (GL-AR300M16) **URL:** \ **Category:** Router\ **Created:** [December 14, 2023, 2:41am UTC](https://forum.gl-inet.com/t/problem-using-printer-on-port-9100-gl-ar300m16/36140 "2023-12-14T02:41:51Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![lpcurcio](https://forum-assets.gl-inet.com/letter_avatar_proxy/v4/letter/l/9d8465/32.png) [@lpcurcio](https://forum.gl-inet.com/u/lpcurcio)\ **Post date:** [December 14, 2023, 2:41am UTC](https://forum.gl-inet.com/t/problem-using-printer-on-port-9100-gl-ar300m16/36140/1 "2023-12-14T02:41:51Z")
In my house I have an Asus AX88U router, distributing addresses in the 192.168.0.x range and another GL-300M16 router distributing addresses in the 10.0.20.x range. These two routers are interconnected via Wifi, with static routing between them. I can ping between computers on both subnets. The problem is that on the GL-300M16 network, there is a label printer (Zebra) that uses port 9100. I can communicate and print labels through a computer on the same subnet (10.0.20.x), but I cannot print from a computer located on the other subnet (192.168.0.x). Remembering that I can ping the printer normally. Do I need to open or forward port 9100? If positive, how do I do it? I tried, but I don’t know if I was doing it correctly. ---
**Author:** ![bring.fringe18](https://forum-assets.gl-inet.com/user_avatar/forum.gl-inet.com/bring.fringe18/32/11777_2.png) [@bring.fringe18](https://forum.gl-inet.com/u/bring.fringe18)\ **Post date:** [December 14, 2023, 11:19am UTC](https://forum.gl-inet.com/t/problem-using-printer-on-port-9100-gl-ar300m16/36140/2 "2023-12-14T11:19:23Z")
Without knowing the specific firmware version of the Shadow (GL GUI -\> System -\> Upgrade) it's hard to tell... but here's how to confirm the port is open. You'll need to SSH into the Shadow. See below for specifics on all that. ```auto root@flint:~# opkg update; opkg install nmap root@flint:~# nmap -p 9100 $printerIPGoesHere ``` > **[Scanning All or Specified Ports With Nmap](https://linuxhandbook.com/nmap-scan-ports/)** > > Nmap is an open source utility for network discovery and security auditing. Learn how to scan specific or multiple or all ports with nmap. > [@HOW-TO: Script: List My OPKGs (to a file for backup)](https://forum.gl-inet.com/t/how-to-script-list-my-opkgs-to-a-file-for-backup/30963): > > Keywords: backup, opkg, plugins, list, howto, script, shell, luci, restore, ipk, tarball, conf Description List user’s (your) installed packages, writing them to a text file that can be used to reinstall the binaries of what a user manually installed. The resulting .list file will be use to opkg install to pull from the feeds. That is done with two commands in one execution. The GL GUI doesn’t feature a backup function. Creating & restoring a backup achieve (.tar.gz, aka tarball) of all your… ---
**Author:** ![lpcurcio](https://forum-assets.gl-inet.com/letter_avatar_proxy/v4/letter/l/9d8465/32.png) [@lpcurcio](https://forum.gl-inet.com/u/lpcurcio)\ **Post date:** [December 14, 2023, 11:53am UTC](https://forum.gl-inet.com/t/problem-using-printer-on-port-9100-gl-ar300m16/36140/3 "2023-12-14T11:53:18Z")
> [@bring.fringe18](#): > > Without knowing the specific firmware version of the Shadow (GL GUI → System → Upgrade) it’s hard to tell… but here’s how to confirm the port is open. You’ll need to SSH into the Shadow. See below for specifics on all that. Thanks for answering. The router is using the latest firmware (4.3.7). I’m sorry, but I don’t have much experience with Nmap and I’m not sure I understand it correctly. I think you want me to check if I can access port 9100 through the GL-AR300M16. What happens is that the printer (10.0.20.101) is part of the LAN of this router (10.0.20.x), so I have no difficulty printing within this subnet. The problem occurs when I try to print from a computer on the Asus router’s subnet (192.168.0.x). I can do a ping test between these networks and everything is OK. The problem seems to be exactly happening with port 9100. I did some tests yesterday using it, including putting both the computer in DMZ mode on the Asus, and I also put the printer in DMZ mode on the GL-AR300M16. The problem persisted. No printing. ---
**Author:** ![bring.fringe18](https://forum-assets.gl-inet.com/user_avatar/forum.gl-inet.com/bring.fringe18/32/11777_2.png) [@bring.fringe18](https://forum.gl-inet.com/u/bring.fringe18)\ **Post date:** [December 14, 2023, 12:03pm UTC](https://forum.gl-inet.com/t/problem-using-printer-on-port-9100-gl-ar300m16/36140/4 "2023-12-14T12:03:11Z")
Ah, 4.3.7; good to know. The GL docs still link to v3. For v4.x, you should find it under GL GUI → Network → Firewall → Open Ports on Router → [Add] . `nmap` is a command line tool to scan for open ports on a remote host/device; in this case I was going to get you to scan whatever subnets you had to confirm the port to the printer’s IP was indeed open. Such tools is also available for phones/mobile devices, if that helps… & features a GUI. This is assuming you, of course, have a Android device & F-Droid already installed for the very best in Free & Open Source Software 😉 (I don’t use Apple & try to stay away from closed sourced software when possible). I’m pretty sure there’d be something similar for iOS, though. If opening the port doesn’t work, I question if Port Forwarding isn’t the method to use here. > **[Ning | F-Droid - Free and Open Source Android App Repository](https://f-droid.org/en/packages/de.csicar.ning/)** > > Ning: Simple and fast local network scanner. Similar to Fing or Nmap > **[Firewall - GL.iNet Router Docs 4](https://docs.gl-inet.com/router/en/4/interface_guide/firewall/)** > > Documentation for GL.iNet Router Productions ---
**Author:** ![bruce](https://forum-assets.gl-inet.com/user_avatar/forum.gl-inet.com/bruce/32/35649_2.png) [@bruce](https://forum.gl-inet.com/u/bruce)\ **Post date:** [October 29, 2025, 4:28am UTC](https://forum.gl-inet.com/t/problem-using-printer-on-port-9100-gl-ar300m16/36140/5 "2025-10-29T04:28:13Z")