vpn/non vpn port scan..

[porkpiehat]

hi, I've just installed a VPN, and ran a port scan.... results were, most were closed and a few open.... whereas when I scan without it all ports are stealthed...what gives?

 

[OokamiCreed]

Not much of a networking person but when you use a VPN, there really isn't much need to stealth ports. There all connect through encrypted servers which you can't just simply tap into whenever you want. Also many computers use the same IP, so even more reason why it don't really matter. Also some ports are open for certain reasons. Like some ports are use for torrenting efficiently. Also known as port forwarding which opens ports.

Someone else can correct me if I'm wrong. I'm just going off what I learned by myself or small time research. I'm sure something in there is wrong. Most likely the first part if anything.

 

[LabZero]

A VPN allows you to establish a secure connection between systems that use internet to exchange data with a remote LAN.

For exchanging these data with the remote LAN, it creates a virtual "tunnel" within which all data is encrypted in such a way that they cannot be monitored or intercepted by third parties, but to do this the VPN must use some ports.

PPTP, L2TP protocols are most used :

PPTP : port TCP 1723
L2TP : port UDP 500, UDP 1701 and UDP 4500.

It is therefore normal to find open ports when you make the port scanning under VPN.

 

[jamescv7]

Actually that's pretty normal on all majority of VPN, if you are going to search in these keywords then related forum answers are provide.

It varies on how tunnel open from specific ports to gather encrypted connection, no security threat should be expose, because not an ordinary connection where you've done always.

 

[OokamiCreed]

Just realized I used the word "also" way to often. Hate when I do that.

A VPN allows you to establish a secure connection between systems that use internet to exchange data with a remote LAN.

For exchanging these data with the remote LAN, it creates a virtual "tunnel" within which all data is encrypted in such a way that they cannot be monitored or intercepted by third parties, but to do this the VPN must use some ports.

PPTP, L2TP protocols are most used :

PPTP : port TCP 1723
L2TP : port UDP 500, UDP 1701 and UDP 4500.

It is therefore normal to find open ports when you make the port scanning under VPN.

This is the type of response I was hoping for someone to have. I only have to add on that PPTP and L2TP aren't as secure as some of the other protocols so I'd recommend not using them. I myself use a VPN (Private Internet Access) that uses OpenVPN which uses SSLv3/TLSv1 protocols. Would also like to add that UDP is faster but a little less stable than TCP, but TCP is more stable but a slower. For general internet usage, I'd use UDP.

 

[LabZero]

I only have to add on that PPTP and L2TP aren't as secure as some of the other protocols so I'd recommend not using them.

Absolutely correct @OokamiCreed (currently i am studying this )

The PPTP protocol is probably the most used to establish VPN connections but it is also the less secure in absolute.
Developed by Microsoft, PPTP supports cryptographic keys up to 128 bits. Data encryption is done using the Microsoft Point to Point Encryption Protocol.
To establish a VPN connection using PPTP, is only required the use of a username, a password and the address of the VPN server

The L2TP protocol, an acronym for Layer 2 Tunnel Protocol is a popular tool used to establish VPN connections,It does not offer any form of security and data in transit are not encrypted.
For this reason, L2TP is usually used "pair" with the IPSec protocol that integrates features of authentication, encryption and identity control of IP packets.

 

[porkpiehat]

so, is it ok that it seems to bypass comodo firewall... or am I missing something?