Good test results, thanks. pppd 2.5.2 offers 40-bit MPPE instead of 128-bit MPPE, the peer offers 128-bit MPPE and MPPC, and this causes pppd to stop LCP with "MPPE required but peer negotiation failed".
During the stop, pppd 2.5.2 rejects 128-bit MPPE but advises MPPC is okay. The peer then explicitly counter-proposes 128-bit MPPE. The options are improperly dumped; /etc/localtime is referenced, and certain options are not printed. Perhaps they are not printable, or not parsed. The require-mppe option, which is critical, is not dumped. Please check your options files for unconventional text, such as carriage-returns or text outside ASCII or UTF-8. hexdump -C may help. On the other hand, the debug and dump options were obeyed even though they were not dumped. Try the require-mppe-128 option instead of require-mppe. ba7f7e0 is the commit after the last one that worked for you. The changes there are extensive; next step would be to break the commit into smaller changes until you find which one does it. References: https://pptpclient.sourceforge.net/howto-diagnosis.phtml#mppe_bits https://pptpclient.sourceforge.net/howto-diagnosis.phtml#confreqacknakrej
