Testing the port question

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Agentshadow
OpenVpn Newbie
Posts: 3
Joined: Fri May 15, 2020 7:44 pm

Testing the port question

Post by Agentshadow » Fri May 15, 2020 7:54 pm

Hi. I have an Asus router flashed with the third-party firmware Asus Merlin. In there I have a VPN setup and I use the OpenVPN App to connect to my VPN in my router. I was concerned about a possible port that may be open in my router so I checked my IP at Shodan, Censys, GRC Shields Up and even Nmapped my WAN IP from a paid-for VPN and despite all that the port of 1194 appears to be closed/filtered. Now my local VPN works fine, it's just that I'm wondering why the port appears to be closed? How is it that I'm able to make a connection to a port that appears closed?

I did some research and it appears that it's hard to Nmap scan a UDP port and OpenVPN? I read about a magic sting and I sent this magic string hex data via Namp and it sent, but no response.

Code: Select all

\\x38\\x01\\x00\\x00\\x00\\x00\\x00\\x00\\x00
So is this magic string still part of OpenVPN or am I doing something wrong in Nmap?

Very curios to find out why and how this port appears to be closed. I thought it was due to port knocking, but there is no port knocking configuration on my part.

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TinCanTech
OpenVPN Protagonist
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Joined: Fri Jun 03, 2016 1:17 pm

Re: Testing the port question

Post by TinCanTech » Fri May 15, 2020 8:42 pm

It is openvpn being smart. Your "magic string" will not work.

Agentshadow
OpenVpn Newbie
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Joined: Fri May 15, 2020 7:44 pm

Re: Testing the port question

Post by Agentshadow » Sat May 16, 2020 3:12 am

Care to elaborate?

Any way to test the port and see if it's open?

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TinCanTech
OpenVPN Protagonist
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Joined: Fri Jun 03, 2016 1:17 pm

Re: Testing the port question

Post by TinCanTech » Sat May 16, 2020 12:10 pm

Agentshadow wrote:
Sat May 16, 2020 3:12 am
Care to elaborate?
Openvpn is very smart about security.
Agentshadow wrote:
Sat May 16, 2020 3:12 am
Any way to test the port and see if it's open?
Use a client to connect, if it connects then the port is open.

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