1. We need to patch the source ppp from Slackware

https://mirrors.slackware.com/slackw...es/source/ppp/ with https://www.nikhef.nl/~janjust/ppp/ install after compile completes

2. Get openssl-1.1.1g-x86_64-1.txz from https://mirrors.slackware.com/slackw...slackware64/n/ We only need to extract the file libcrypto.pc from it

3. Compile the pptp from https://slackbuilds.org/repository/14.2/network/pptp/ I'm using pptp-1.10.0-x86_64-1.txz

4. Compile the NetworkManager-pptp from https://slackbuilds.org/repository/1...kManager-pptp/

5. Backup your original libcrypto.pc to a safe location and replace it with the newer version to /usr/lib64/pkgconfig/

6. Compile the NetworkManager-l2tp from https://slackbuilds.org/repository/1...kManager-l2tp/ I'm using 1.8.2 https://github.com/nm-l2tp/NetworkManager-l2tp
after compile completes, replace newer libcrypto.pc with original from the backup

7. Compile the strongswan from https://slackbuilds.org/repository/1...?search=strong I'm using strongswan-5.8.4-x86_64-1.txz

8. Compile the xl2tpd from https://slackbuilds.org/repository/1.../?search=xl2tp I'm using xl2tpd-1.3.15-x86_64-1.txz

I can enjoy my L2TP/PPTP + IPSec server with a gui. YAY!!

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Well done. I tried a few times to get this going without enjoying the success you have.

In the end, I gave up and set up an OpenVPN server at the office because all the parts were already there. The GUI client for NM was recently added to Slackware-current and seems to work quite well.

I have been dealing with L2TP Servers for a while and needed to do it with Slackware. Hopefully this will help others out who prefer a gui. Configuring all config files can become tedious on the terminal.

@PROBLEMCHYLD

Hi, Thanks for this; they have changed the vpn access at my work to l2p/ipsec, so forced to go down this rabbithole. (Of course they provided unbuntu-only advice of how to set this up...)

Assuming this recipe is for 14.2, have you any idea whether this works on current? And what to do now pam is there (whatever it does; most of this networking access stuff does my head in)?

Ah well, I tried, but did not get far: the most current patches from the nikhef link ( eaptls-mppe-1.201.patch, eaptls-mppe-1.202.patch, eaptls-mppe-1.300.patch, eaptls-mppe-1.301.patch) applied as
after the zcat patch lines at lines 83-84 in the /source/n/ppp.SlackBuild, cause all kinds of -R warnings/errors during patching.
This is the first of many and it seems pointless to continue....;
What mistake am I making?

Cheers,

rob

You only need to install one patch v1.301 which is the latest.

1 members found this post helpful.

I came across this some time ago. I hope it's useful; I'm using OpenBSD for my VPN these days.

It covers L2TP/IPSec and the newer and more secure(?) IPsec VPN type -- IKEv2.

I used that method as well, but prefer the gui approach, see here https://www.linuxquestions.org/quest...ml#post5882731

Fab, that worked, thanks.

Welcome....

Ok, I got the gui running, thanks; but that -of course- doesn't mean much when the backends don't communicate... a couple of months ago the gui also started up fine but it did not connect; but this was without the (networkmanager) pptp packages nor the ppp-patch so when I stumbled on this post it gave hope that these were the missing links.... But still there is something not happening even after converting all '.conf.new' in /etc to '.conf' which, at least, made the logs a bit more lively...:

The only thing I am suppose to put into the gui is a user name, passphrase, a shared key plus the phase 1 and phase 2 algorithms; no certificates etc.

Why would it stop at the ppp stage; what is missing (apart from my understanding of this all)??

Are you using certificates or Pre-shared key? I only use certificates because of the security. You have to explain more details for me and others to help. You configure everything in Networkmanager not the .conf files. Look at the screenshots in the first post.

As mentioned in the last lines above, it is a preshared key that's used; they possibly want to keep it simple for all the windows users. My setup at home from where I try to access my work is : world <-> modem <-> dd-wrt-router-using-openvpn <-> laptop.
Maybe the line above "Aug 6 00:43:57 .. charon: 01[IKE] local host is behind NAT, sending keep alives " reflects that.

I tried including the google dns addresses in the /etc/stronswan.conf as advised on the link Gerard Lally provided but this did not make a difference.

For the rest I have not done anything else than as described above or in your post (omitted the libcrypto exchange trick as I am on current). But the ppp-error is something I ran into last time I tried this as well. Is there someting that needs setting on the vpn-router (but why; its just the tunnel it goes through...)?

EDIT: found this in /var/log/debug which appears to span the bit where it falters:

EDIT-3 removed previous nonsense; it fails on the ppp exchange

I'm not sure if I can be of any more help since I'm not on current and don't use PSK. Try downgrading strongswan to and older version. I know 5.9.0 is new but I use 5.8.4, also try configuring your ppp/ipsec vpn adapter settings in NetworkManager instead of .conf. I have never gotten PSKs to work is why I use certificates.

Hi, thanks for the suggestions. Your last line tells all. Seems sufficient reason not to waste more time on trying to make this work (it seems more sense to change the PSK policy...).

strongswan 5.9.0 seems to work, set all your configs to default PPP, L2TP IPSEC XL2TPD strongswan etc... and configure like so in the screenshot, as you can see, I have an active connection but with certificates.

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