Email Notification - OpenVPN Client Connect (Common Name)

[Gertjan]

To all : Test your VPN notification first !!

Go outside, de activate the Wifi, activate the VPN , take a big walk, swim, drive or best : take a plane.

When you get back, you'll be in for a surprise.
This surprise includes :
The huge number of mails you received.
Maybe also the mail from your mail host that states that they detect a spam bomb attack .... and that they stopped treating further mails from this 'source'.
You used another outside service : Leave your chair, take a big walk, swim, drive or best : take a plane. ? Fine : they will blacklist you, as their server has to be protected.
Etc.

It's not only about knowing what PHP is : that's an easy one : you wana drive that car ? => Go for the license (and insurance, maintenance, etc)

I'll leave this question open for now : Why did you receive hundreds, if not thousands of nearly 'notification' identical mails ?

The code given as an example above has to be .... worked on.
For example : the call to "geoiplookup.net" : it should be used wisely :
When a the VPN connect script is called, the IP obtained should be compared with the content of a file. this file contains all the IPs found in VPN connect messages.
If the IP is found : do nothing, as the IP is know.
The IP is not in the file : have it looked up, and send the mail.

Now you will receive far less mails, and no one will complain.

And I have a question : Normally, VPN access is given to people that you some how trust.
Why GEO locate them ?
Your kids ?
And then there is the eternal discussion that GEOIP data is quiet useless.
There are no more free IPv4s, it became a rare resource. The last blocks are sold often, broken up, sold again, from anywhere to anywhere. Their actual location isn't really known any more.
And take Apple and IBM for example : back then, they bought and entire /8 (or close to that). And all their IP's are in (example) Redmond, although used world wide.
With IPv6 thinks get better : You can forget the notion of GEOIP as no one can build the database that can hold all the details : there are not enough resources on this planet left to do so. Maintaining and giving access to this database will be even more difficult.

[noplan]

WORD !

[boggie1688]

@serbus Thank you for this, this would have taken me ages to figure out. Specifically the function preg_match. I was googling around and though perhaps XPATH was the right function.

[boggie1688]

@gertjan

I tested my VPN while moving in a car, and I see what you are saying about multiple emails coming through. As my cell reception dropped and reconnected, the notify and disconnect scripts would run.

If I'm honest, the VPN isn't used in a setting with multiple users. There is only one, who isn't very tech savy. Additionally they will only be using it on a desktop. I don't anticipate a crazy amount of emails as I doubt they will login more than once a week.

The geo data is just to confirm that my one user is indeed my who I expect it to be. IE coming from roughly the geographical area that I expect. Probably a really weak way to check, but as you can see I'm not that tech savvy.

[PM_13]

@boggie1688
"If I'm honest, the VPN isn't used in a setting with multiple users."

VPN are more widely used on larger networks but it is not typical for admins to set up receiving emails for each VPN user connect/disconnect session.

The reason being - a VPN user by definition is a trusted user. In addition to having credentials (user name and password), a VPN user also needs a signed certificate.

[noplan]

@pm_13 said in Email Notification - OpenVPN Client Connect (Common Name):

is not typical for admins to set up receiving emails for each VPN user connect/disconnect session

wrong !
it was not used to be before COVID

now a ton of admins use
the exact output of Post 26 from this topic

https://forum.netgate.com/topic/151351/email-notification-openvpn-client-connect-common-name/26

to get a view of what is goin on in HomeOffice and why, not to mention the information when a
contractor is entering the network as a trusted user.

dont get me wrong but there is a point of gettin notification via mail
but there is no point as @Gertjan mentioned earlier in geoIPlookUps

btw it would be nice if someone feels free to write the information from the mail
in a csv file to send it once a week via cron and mail to the admin stuff
so you get a nice n sweet reporting of your VPN users (it's still on my toDo list but my coding skill isnt good enough ;)

brNP

[bingo600]

Fun with ovpn connect/disconnect scripts.

Using ssh directly to the firewall , select 8 for shell.

NOTE: Don't do this while working via a VPN server that uses these scripts
If you FSCK' up the php connect script , and the script returns an error. OpenVPN will reject new connects.

I made a /root/ovpn-connect.sh file , and pasted this into it.

#!/usr/local/bin/php -q
<?php
	require_once("/etc/inc/notices.inc");
	$local_connect_value = __FILE__ . " \n user_name: " . getenv('common_name') . " \n vpn_client_ip: " . getenv('ifconfig_pool_remote_ip') ." connected from " . getenv('trusted_ip') . " on " . date('F j, Y, g:i a');
	if ( strpos (__FILE__ , 'ovpn-disconnect') !== false ) {
	$local_connect_value .= ", \n duration : " . round(((getenv('time_duration'))/3600),2) . "  hours, or " . round(((getenv('time_duration'))/60),2) . "  minutes, or " . getenv('time_duration') . "  seconds,\n upload from vpn-client (received) : " . round(((getenv('bytes_received'))/1048576),2) . " MB, \n download to vpn-client (send) : " . round(((getenv('bytes_sent'))/1048576),2) ." MB. \n DISCONNECTED.";
	}
	notify_all_remote($local_connect_value);
?>

Made it executeble:

chmod +x /root/ovpn-connect.sh

Copied it to /root/ovpn-disconnect.sh

cp /root/ovpn-connect.sh  /root/ovpn-disconnect.sh

Activated it in the OpenVPN Server -> Advanced Configuration

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Done !

Edit:
Im my e-mail client (thunderbird) i made a filter that triggers :
If From contains : My Notifications -> From e-mail address
And Body Contains : /root/ovpn
Move mail to : Ovpn e-mail Connect folder

[bingo600]

What i learned , and did different from the above solutions:

1:
DON'T symlink the disconnect script to the connect script.
As nice (and logical) as this seems to be , your disconnect section won't work.
As FILE will resolve symlinks too , and you'll end up with the connect filename for both connect & disconnect.

From : https://www.php.net/manual/en/language.constants.predefined.php

__FILE__ 	The full path and filename of the file with symlinks resolved. If used inside an include, the name of the included file is returned.

I have included the the passed FILE variable in the e-mail body to verify that.

2:
The use of strrchr funct. here , seems bogus to me.

if ( strrchr (__FILE__ , 'disconnect') )

From : https://www.php.net/manual/en/function.strrchr.php
strrchr — Find the last occurrence of a character in a string

I want a full string match , not a character match.

I replaced that with strpos()
Watch out .. the !== false is not a kludge.

if ( strpos (__FILE__ , 'ovpn-disconnect') !== false ) 

I could have used different connect & disconnect files , and skipped the file match of "disconnect".
But the challenge of detecting & resolve the FILE variable had to be overcomed

So even though they are two separate files , the contents are equal.

Hope it's usable for someone

/Bingo

[Gertjan]

@bingo600 said in Email Notification - OpenVPN Client Connect (Common Name):

DON'T symlink the disconnect script to the connect script.

That breaks the script.

Because this :

if ( strrchr (__FILE__ , 'disconnect') )

The "disconnect.sh" should contain the word "disconnect" so it knows it's called on a disconnect event.

"strrchr " means the word "disconnect" should exist in the file name.

You can of course use seperate files for both events.
Or choose other file names, but in that case, the _FILE search has to be adapted, if needed.

[bingo600]

@gertjan
Nope ...

From : https://www.php.net/manual/en/function.strrchr.php
strrchr — Find the last occurrence of a character in a string

I'we used that functions tonzz of times in "C".

Edit: Re: symlink
If you prepend the FILE . as below , you'll see how it's resolved in your e-mail body.
connect vs disconnect.

$local_connect_value = __FILE__ . " \n user_name: " 

[bingo600]

@gertjan said in Email Notification - OpenVPN Client Connect (Common Name):

You can of course use seperate files for both events.
Or choose other file names, but in that case, the _FILE search has to be adapted, if needed.

I totally agree here ... Match the __FILE with the filename used for disconnect

/Bingo

[noplan]

@bingo600

and what does the output look like ?

something like that, and this txt file will
a) be mailed to admin via cron each Sunday morining 09:00
b) will be cleared each Sunday morning 09:05 after file was mailed
(storing a backup of this file would be pretty cool ) just in case the mail isnt workin ;)

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Then the rest is up to som fancy XLS reporting stuff ;)
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helps you out comparing the billed hours on your system with the real hours they spend on it.

[bingo600]

@noplan said in Email Notification - OpenVPN Client Connect (Common Name):

@bingo600

and what does the output look like ?

I just added the called filename to the output.
And fixed the "stringcompare"

Rest is the same.

Credit for the script & decoding the env vars , should go to the original authors.

/Bingo

[Armstrong]

This post is deleted!

[newnub]

Apparently there is a bug with FreeRADIUS and Assigned IPv4 Address for your OpenVPN if you use the email script by adding it to:
OpenVPN Server -> Advanced Configuration > Custom Options

If you invoke script from Custom Options under OpenVPN Server -> Advanced Configuration, then FreeRADIUS will no longer assign your static IPv4 for OpenVPN. I don't know how to get around this but just FYI if suddenly your OpenVPN IP is no longer your defined static address.

[Stewart]

I know this thread is kinda old but I don't know that starting a new topic is the best course of action. I'm trying to implement this but there is a delay of a couple of minutes on the disconnect script and the connect script won't log if it's waiting for the disconnect script.

In the Advanced Configuration -> Custom Options I have:
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I've modified the scripts to both send an email and output to a log file when run. When a client connects, I see the log file updated immediately and the email comes very quickly. When a client disconnects it takes 2 -2.5 minutes before the log file is updated and the email is sent. During that window of time if I reconnect it doesn't log or send an email. There is very little difference in the two scripts at this point as I try to narrow down the issue.

Does anyone have any idea what this delay is and what's going on?

[Gertjan]

@stewart said in Email Notification - OpenVPN Client Connect (Common Name):

kinda old

Nothing changed.

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My /root/notify.sh file :

#!/usr/local/bin/php -q
<?php
	require_once("/etc/inc/notices.inc");
	$local_connect_value = " user_name: " . getenv('common_name') . " vpn_client_ip: " . getenv('ifconfig_pool_remote_ip') . " on " . date('F j, Y, g:i a');
	log_error("About to send a mail : Connecting");
	notify_all_remote($local_connect_value);
?>

The disconnect.sh file :

#!/usr/local/bin/php -q
<?php
	require_once("/etc/inc/notices.inc");
	$local_connect_value .= ", during : " . getenv('time_duration') . " seconds, received : " . getenv('bytes_received') . " bytes, send : " . getenv('bytes_sent') ." bytes. DISCONNRECTED.";
	log_error("About to send a mail : Disconnecting");
	notify_all_remote($local_connect_value);
?>

The files :

ls -al *.sh
-rwxr-xr-x  1 root  wheel  353 Sep  8 08:13 disconnect.sh
-rwxr-xr-x  1 root  wheel  316 Sep  8 08:14 notify.sh

I connected to my pfSense VPN server, and disconnected a couple of seconds later.

My centralized syslog server showed :

...
2021-09-08 08:21:32	User.Error	pfsense	1 2021-09-08T08:21:35.264334+02:00 pfsense.my-network.tld php 15669 - - /root/notify.sh: About to send a mail : Connecting
2021-09-08 08:21:35	User.Error	pfsense	1 2021-09-08T08:21:37.728863+02:00 pfsense.my-network.tld php 15908 - - notify_monitor.php: Message sent to my-gmail@gmail.com OK
....
2021-09-08 08:21:49	User.Error	pfsense	1 2021-09-08T08:21:52.325734+02:00 pfsense.my-network.tld php 16254 - - /root/disconnect.sh: About to send a mail : Disconnecting
2021-09-08 08:21:51	Daemon.Warning	pfsense	1 2021-09-08T08:21:54.188458+02:00 pfsense.my-network.tld radvd 93362 - - sendmsg: Permission denied
2021-09-08 08:21:56	User.Error	pfsense	1 2021-09-08T08:21:58.979760+02:00 pfsense.my-network.tld php 15908 - - notify_monitor.php: Message sent to my-gmail@gmail.com OK
....

You can also use a console or SSH session, and execute :

tail -f /var/log/system.log

to see real time system log events.

Logs lines showed up instantly.
I received the mails.

[Stewart]

@gertjan said in Email Notification - OpenVPN Client Connect (Common Name):

@stewart said in Email Notification - OpenVPN Client Connect (Common Name):

kinda old

Nothing changed.

I only mentioned it because I'm always wary of necroposting and people getting upset. I'm sure it isn't the scripts themselves. Even if I have client-connect and client-disconnect call the same script the delay is still there. Would it matter if the OpenVPN server is set to Remote Access (SSL/TLS + User Auth) and authenticated by the Active Directory?

[Gertjan]

@stewart said in Email Notification - OpenVPN Client Connect (Common Name):

Even if I have client-connect and client-disconnect call the same script the delay is still there.

I was using the same file for the connect / disconnect event, but @bingo600 has a point - see above.
The OpenVPN connect and disconnect are instantaneously for me.

I'm using myself SSL/TLS only.
Authentication (using AD) only happens when the user logs in.

[Stewart]

@gertjan

I'm using different scripts for each event but tried it with the same script to rule it out.