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user757306
Asked: 2019-11-02 00:48:55 +0800 CST

Ubuntu 19.10 l2tp VPN doesn't work anymore

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After upgrading from Ubuntu 19.04 to Ubuntu 19.10, my VPN connection doesn't work anymore.

My settings:

phase1: 3des-sha1;modp1024
phase2: 3des-sha1

This worked fine so far.
I checked the packages installed: 

network-manager-l2tp 1.2.10-1; 
network-manager-l2tp-gnome 1.2.10-1; 
xl2tpd 1.3.12-1.1
libreswan 3.29-2

What can I do?

vpn upgrade 19.10 l2tp

3 Answers

  1. Apparently, Ubuntu is not really happy with using 3des as handshake cipher, but I managed to make it work.

    You may want to set the phase 1 and 2 algorithms using a final exclamation mark, like so:

    Phase 1: 3des-sha1-modp1024! Phase 2: 3des-sha1!

    I tested this with network-manager-l2tp 1.2.10-1, network-manager-l2tp-gnome 1.2.10-1 and Ubuntu 19.10

    Hope this solves your issue too.

    Regards.

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  2. I had the exact same problem upgrading from 19.04 to 19.10. I tried the NetworkManager upgrade too, but that didn't solve my problem. I then did the following three things, and now everything works again:

    1. Replaced libreSwan with StrongSwan (I found if I purged libreSwan, StrongSwan was automatically installed)
    2. Explicitly specified the Phase 1 and Phase 2 algorithms: "3des-sha1-modp1024" and "3des-sha1" respectively.
    3. Ensured only MSCHAPv2 was checked under PPP Settings.

    I have a feeling #3 is what solved my problem as I did notice a few more authentication boxes were checked under PPP Settings after the upgrade.

    • 1

  3. Try the network-manager-l2tp 1.2.16-1 backport from the following PPA:

    With network-manager-l2tp 1.2.16-1, you should be able to delete the phase 1 & 2 algorithm entries as it now uses a merge of proposals from Win10 and iOS instead of using the libreswan or strongswan default set of proposals.

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