How can I check that the VPN is secure?

RichTJ99

Hi,

I have my VPN setup using DD-WRT. I am able to RDP, get to network drives, & everything works great. I have two questions:

1. I thought that when VPN'ing into my network, that my external IP would change to the SOHO network's external IP. That is not the case, I still have the external IP of my current ISP. This makes me wonder if my SOHO traffic might be at risk.

2. Is there a way to test that the VPN traffic is secure?

3. I notice when launching the VPN from a client, that no password is asked. While I dont expect to lose a laptop, I do wonder if it makes sense to have a password that I can change.

Thanks,
Rich

janjust

1. I thought that when VPN'ing into my network, that my external IP would change to the SOHO network's external IP. That is not the case, I still have the external IP of my current ISP. This makes me wonder if my SOHO traffic might be at risk.

that depends on your setup; if you are using

push "redirect-gateway def1"

on the server then your IP address should change to the address of the VPN server, provided that you've got routing right.

2. Is there a way to test that the VPN traffic is secure?

run wireshark on the external interface (i.e. eth0) and browse to a website - you should not see HTML text fly by, just garbled data

3. I notice when launching the VPN from a client, that no password is asked. While I dont expect to lose a laptop, I do wonder if it makes sense to have a password that I can change.

you can set a password on the client certificate, or you can add username/password authentication. If you lose a laptop you can always revoke the certificate that was stored on the laptop ; this does show that proper key management is necessary!

RichTJ99

JJK,

Thanks for getting back to me! I appreciate it! I am really finding this fun to play with.

1. How do I check to see if i have the routing right (not exactly sure what you mean)? I log in, it does give me the same IP on the VPN as the SOHO, so I guess thats good.

2. Actually, I ended up remoting into one of my client PC's, installing openvpn, & testing it that way. The source & destination using wireshark showed now HTTP traffic. The only source/destination was the local IP on the client end and my SOHO WAN Ip. I guess thats secure then!

3. I agree that key management is important for just this type of situation. I didnt see where I can add a password to the certificate or where I could add another password when connecting. Is one method more secure than another?

Thanks,
Rich

janjust wrote
1. I thought that when VPN'ing into my network, that my external IP would change to the SOHO network's external IP. That is not the case, I still have the external IP of my current ISP. This makes me wonder if my SOHO traffic might be at risk.
that depends on your setup; if you are using
push "redirect-gateway def1"
on the server then your IP address should change to the address of the VPN server, provided that you've got routing right.

2. Is there a way to test that the VPN traffic is secure?
run wireshark on the external interface (i.e. eth0) and browse to a website - you should not see HTML text fly by, just garbled data

3. I notice when launching the VPN from a client, that no password is asked. While I dont expect to lose a laptop, I do wonder if it makes sense to have a password that I can change.
you can set a password on the client certificate, or you can add username/password authentication. If you lose a laptop you can always revoke the certificate that was stored on the laptop ; this does show that proper key management is necessary!

janjust

1. How do I check to see if i have the routing right (not exactly sure what you mean)? I log in, it does give me the same IP on the VPN as the SOHO, so I guess thats good.

if you're redirecting all traffic via the VPN then you also need to make sure routing on the server end is set up correctly, or you won't browse the internet at all; if a site like http://www.whatismyip.com shows your VPN server address then you're all set

3. I agree that key management is important for just this type of situation. I didnt see where I can add a password to the certificate or where I could add another password when connecting. Is one method more secure than another?

when building a certificate you can use

build-key-pass

which prompts for a client passphrase. Alternatively you can add a passphrase (password) to an existing client key using

openssl rsa -des3 -in client1.key -out newclient.key

RichTJ99

I was also curious, using a client PC connecting remotely to the VPN, I am able to ping a computer on the local SOHO. If I am on the SOHO & try to ping a computer connecting via VPN, I am unable to ping it (weird)?

Ok, in terms of keys with passwords.

Would this is the order I did it without a password:

vars
clean-all
build-ca

build-key-server server

build-key client1

build-dh

You mentioned using "build-key-pass" but I dont see that batch file but I do see it mentioned in the how to . I like the idea of making a new password client.

Where would I use this?

openssl rsa -des3 -in client1.key -out newclient.key

Do I add that to the client.conf file? For the newclient.key, do I just make a text file with the password, then change the extension to .key?

Thanks,
Rich

janjust

Reply with quote Post Posted: 13 May 2011 19:40
Re: How can I check that the VPN is secure?
I was also curious, using a client PC connecting remotely to the VPN, I am able to ping a computer on the local SOHO. If I am on the SOHO & try to ping a computer connecting via VPN, I am unable to ping it (weird)?

Ok, in terms of keys with passwords.

Would this is the order I did it without a password:
Code:
vars
clean-all
build-ca

build-key-server server

build-key client1

build-dh

You mentioned using "build-key-pass" but I dont see that batch file but I do see it mentioned in the how to . I like the idea of making a new password client.

oh crap , I forgot, the windows batch files don't include 'build-key-pass' ....

Where would I use this?
Code:
openssl rsa -des3 -in client1.key -out newclient.key

this is actually a command you would run in a Windows CMD shell; go to the directories where your keys and certs are located and type in this command; if openssl.exe is not in your PATH then prepend

"c:\program files\openvpn\bin\

to it. ("program files (x86)" on 64bit windows).