[CentOS] VPN suggestions centos 6, 7

Tue Apr 19 09:03:33 UTC 2016
david <david at daku.org>

At 09:09 AM 4/18/2016, you wrote:
>On Mon, 18 Apr 2016, david wrote:
>>I had lots of suggestions, and the most persuasive was to try 
>>OpenVPN.  I already had a CA working, so issuing certificates was 
>>easy.  The HOW-TO guides were less helpful than I could hope, but 
>>comparing several of them, applying common sense, and trying things 
>>out, I arrived at a dead-end. Here's essentially what happened:
>>- None of the HOW-TOs were very clear about the need to add some 
>>attributes to a certificate, keyUsage and extendedKeyUsage.  They 
>>had different values for server and client.  OpenSSL documentation 
>>was a big vague on how to add them, but I think I did - the print 
>>out of the entity certificates showed the values.  The attempt to 
>>connect failed.  The client log is below.  I think it's complaining 
>>that the CA certificate doesn't have the ke Usage extension, which 
>>makes no sense to me.  Such an extension should be in the 
>>end-entity certificate, not the CA's, unless I'm wrong.  I checked 
>>the server and really think that the certificates are in the right place.
>Here's how I managed that in my openssl.cnf file. Lots of bits 
>ellided for clarity's sake:
>### start ###
>[ ca ]
>default_ca = CA_default
>[ CA_default ]
>x509_extensions = server_cert
>[ server_cert ]
>keyUsage = nonRepudiation, dataEncipherment, digitalSignature, keyEncipherment
>extendedKeyUsage = serverAuth, clientAuth
>nsCertType = server, client
>### end ###
>I think the nsCertType directive may be unnecessary these days, but 
>I keep it around because it doesn't hurt anything.
>The important bit is the extendedKeyUsage line; I'm pretty sure that 
>an OpenVPN server needs the serverAuth extension. For instance, here 
>is the X509 extensions configuration for a server used by EasyRSA:
>   basicConstraints = CA:FALSE
>   subjectKeyIdentifier = hash
>   authorityKeyIdentifier = keyid,issuer:always
>   extendedKeyUsage = serverAuth,clientAuth
>   keyUsage = digitalSignature,keyEncipherment
>You can ask openssl to tell you the purpose of a certificate:
>[bash]$ openssl x509 -noout -purpose -in cert.pem  | grep SSL
>SSL client : Yes
>SSL client CA : No
>SSL server : Yes
>SSL server CA : No
>Netscape SSL server : Yes
>Netscape SSL server CA : No
>Anyway, those are the extensions that should do away with these errors:
>>Mon Apr 18 05:34:50 2016 VERIFY OK: depth=1, C=US, ST=California, 
>>L=San Francisco, OU=Certificate Authority, O=XXXX, CN=X.X.X
>>Mon Apr 18 05:34:50 2016 Certificate does not have key usage extension
>Paul Heinlein <> heinlein at madboa.com <> http://www.madboa.com/

Two things...
First, the diagnostic I got referenced the server's CA 
certificate.  And that confuses me.

Second, when I look server's purpose, using the openssl x509 -purpose 
command, I get:

SSL client : No
SSL client CA : No
SSL server : Yes
SSL server CA : No
Netscape SSL server : Yes
Netscape SSL server CA : No

When looking at the CLIENT's purpose, I get

SSL client : Yes
SSL client CA : No
SSL server : No
SSL server CA : No
Netscape SSL server : No
Netscape SSL server CA : No

The difference between what I have and what you reported is that I've 
got SSL Client NO on the server, and SSL server NO on the client, 
which makes sense to me.
The CA certificate itself, says:

Certificate purposes:
SSL client : Yes
SSL client CA : Yes
SSL server : Yes
SSL server CA : Yes
Netscape SSL server : Yes
Netscape SSL server CA : Yes
S/MIME signing : Yes
S/MIME signing CA : Yes
S/MIME encryption : Yes
S/MIME encryption CA : Yes
CRL signing : Yes
CRL signing CA : Yes
Any Purpose : Yes
Any Purpose CA : Yes
OCSP helper : Yes
OCSP helper CA : Yes
Time Stamp signing : No
Time Stamp signing CA : Yes

Advice would be appreciated.