As a few people pointed to this bug report, just a few comments. The following error message in the logs in regard to the VPN server not allowing the EAP authentication method to authenticate:
pppd[5258]: peer doesn't want to authenticate us with eap Disabling EAP in the VPN connections PPP options should fix that issue. In regard to MPPE support, network-manager-l2tp's MPPE support has been broken for over 10 years when Compression Control Protocol (CCP) was disabled with the following commit in its source code: https://github.com/nm-l2tp/NetworkManager-l2tp/commit/5fe98f70344e842faa28014be7ba259c2db7ae8b MPPE generally only works with L2TP servers that don't use IPsec. MPPE negotiations need to happen within CCP and was fixed with the version of network-manager-l2tp that shipped with Ubuntu 24.04. When MPPE is successfully negotiated, the following now appears in the logs (or similar for MPPE 40 or 64-bit) : MPPE 128-bit stateless compression enabled -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2078529 Title: L2TP/IPSec VPN stopped working after upgrade to Ubuntu 24.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager-l2tp/+bug/2078529/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
