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Does the CM1000v2 cable modem have a firewall?
When I scan two specific ports from outside my home they show as blocked.
nmap -Pn -T4 -p 25,9000 "IP address"
Starting Nmap 6.40 ( http://nmap.org ) at 2022-01-03 16:54 UTC
Nmap scan report for machine.name.com (IP address)
Host is up.
PORT STATE SERVICE
25/tcp filtered smtp
9000/tcp filtered cslistener
Nmap done: 1 IP address (1 host up) scanned in 2.14 seconds
I've left out the actual machine name and IP address above, for maybe obvious reasons.
I looked through all of the settings on the admin pages via 192.168.100.1 and found nothing that looks to me like firewall or port blocking. Did I miss something? Does the CM1000v2 modem have firewall capability? If so, how can I open the two ports?
Thanks much.
CM series modems are modems only. No built in router or firelwall. If you have the CM series modem, you'll need to connect a external wifi router to the modem then configure as needed. Most current router firewall are all automatic with little or no user configurations needed.
If you need a actual firewall applicance device, then you need to connect a firewall device. Do a search as there are many. Sorry, I can't recommend anything.
8 Replies
CM series modems are modems only. No built in router or firelwall. If you have the CM series modem, you'll need to connect a external wifi router to the modem then configure as needed. Most current router firewall are all automatic with little or no user configurations needed.
If you need a actual firewall applicance device, then you need to connect a firewall device. Do a search as there are many. Sorry, I can't recommend anything.
I suspected that the CM1000v2 modem wasn't blocking traffic. I also have a R6400v2 router, which is connected to the LAN port of the modem. I need to forward two ports to a couple machines, and I know how to do that. It looks like traffic on those ports isn't even reaching the router. My conjecture is that the traffic is blocked by my ISP. They told me I needed to contact Netgear to make sure their products are set up right. I'm pretty sure everything is OK. But, I'm trying to make sure with experts like you.
Thanks FURRYe38!
Ya, once you have the router set you'll should be good.
Be sure to save off a back up configuration to file for safe keeping. Saves time if a reset is needed.
https://kb.netgear.com/24231/How-do-I-back-up-the-router-configuration-settings-on-my-Nighthawk-router
Enjoy. 📡