PPP - VPN PPTP elimina a conexão com mensagem de depuração estranha

Question

Estou tentando estabelecer um link entre um servidor PPTP Win2008R2 e um cliente Debian 8 usando PPP.

Ao se conectar ao servidor VPN, a autenticação é bem-sucedida. Após a autenticação, está negociando as configurações do MPPE, mas depois da primeira mensagem enviada do ConfReq, o servidor envia de volta uma mensagem TermReq e, portanto, a conexão cai.

Passei horas pesquisando e adicionando ou alterando opções, mas não consigo encontrar nenhuma solução :(

Configurações:

peers / omoffice

pty "pptp <hostname> --nolaunchpppd"
    lock
    noauth
    nobsdcomp
    nodeflate
    name <username as specified in secrets>
    remotename omoffice
    ipparam omoffice
    file /etc/ppp/omoffice_options.pptp

omoffice / options.pptp

lock
noauth
nobsdcomp
nodeflate

refuse-pap
refuse-eap
refuse-mschap
refuse-chap
require-mschap-v2

require-mppe-128
require-mppe

lcp-echo-failure 5
lcp-echo-interval 60

ipcp-accept-local
ipcp-accept-remote
noipdefault

mtu 1200
usepeerdns

Log de depuração

root@NWSS001:/etc/ppp# pppd call omoffice debug dump logfd 2 nodetach noauth
pppd options in effect:
debug           # (from command line)
nodetach                # (from command line)
logfd 2         # (from command line)
dump            # (from command line)
noauth          # (from command line)
refuse-pap              # (from /etc/ppp/omoffice_options.pptp)
refuse-chap             # (from /etc/ppp/omoffice_options.pptp)
refuse-mschap           # (from /etc/ppp/omoffice_options.pptp)
refuse-eap              # (from /etc/ppp/omoffice_options.pptp)
name <username>          # (from /etc/ppp/peers/omoffice)
remotename omoffice             # (from /etc/ppp/peers/omoffice)
                # (from /etc/ppp/omoffice_options.pptp)
pty pptp <hostname> --nolaunchpppd             # (from /etc/ppp/peers/omoffice)
crtscts         # (from /etc/ppp/options)
                # (from /etc/ppp/options)
asyncmap 0              # (from /etc/ppp/options)
mtu 1200                # (from /etc/ppp/omoffice_options.pptp)
lcp-echo-failure 5              # (from /etc/ppp/omoffice_options.pptp)
lcp-echo-interval 60            # (from /etc/ppp/omoffice_options.pptp)
hide-password           # (from /etc/ppp/options)
ipcp-accept-local               # (from /etc/ppp/omoffice_options.pptp)
ipcp-accept-remote              # (from /etc/ppp/omoffice_options.pptp)
ipparam omoffice                # (from /etc/ppp/peers/omoffice)
noipdefault             # (from /etc/ppp/omoffice_options.pptp)
usepeerdns              # (from /etc/ppp/omoffice_options.pptp)
nobsdcomp               # (from /etc/ppp/omoffice_options.pptp)
nodeflate               # (from /etc/ppp/omoffice_options.pptp)
require-mppe            # (from /etc/ppp/omoffice_options.pptp)
require-mppe-128                # (from /etc/ppp/omoffice_options.pptp)
noipx           # (from /etc/ppp/options)
using channel 17
Using interface ppp0
Connect: ppp0 <--> /dev/pts/1
sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xec7eb53a> <pcomp> <accomp>]
rcvd [LCP ConfReq id=0x0 <mru 1400> <auth eap> <magic 0x10494137> <pcomp> <accomp> <callback CBCP> <mrru 1614> <endpoint [local:d4.6e.95.0f.3c.fa.4f.c4.91.60.3c.04.7f.a8.9a.ee.00.00.00.00]>]
sent [LCP ConfRej id=0x0 <callback CBCP> <mrru 1614>]
rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0xec7eb53a> <pcomp> <accomp>]
rcvd [LCP ConfReq id=0x1 <mru 1400> <auth eap> <magic 0x10494137> <pcomp> <accomp> <endpoint [local:d4.6e.95.0f.3c.fa.4f.c4.91.60.3c.04.7f.a8.9a.ee.00.00.00.00]>]
sent [LCP ConfNak id=0x1 <auth chap MS-v2>]
rcvd [LCP ConfReq id=0x2 <mru 1400> <auth chap MS-v2> <magic 0x10494137> <pcomp> <accomp> <endpoint [local:d4.6e.95.0f.3c.fa.4f.c4.91.60.3c.04.7f.a8.9a.ee.00.00.00.00]>]
sent [LCP ConfAck id=0x2 <mru 1400> <auth chap MS-v2> <magic 0x10494137> <pcomp> <accomp> <endpoint [local:d4.6e.95.0f.3c.fa.4f.c4.91.60.3c.04.7f.a8.9a.ee.00.00.00.00]>]
sent [LCP EchoReq id=0x0 magic=0xec7eb53a]
rcvd [CHAP Challenge id=0x0 <df68f4d085f927160c84928c8864604c>, name = "SBS2011"]
added response cache entry 0
sent [CHAP Response id=0x0 <<redacted>>, name = "<redacted username>"]
rcvd [LCP EchoRep id=0x0 magic=0x10494137]
rcvd [CHAP Success id=0x0 "S=1017EFA7032050D6746BFF44A739A6E7B2F5D824"]
response found in cache (entry 0)
CHAP authentication succeeded
sent [CCP ConfReq id=0x1 <mppe +H -M +S +L -D -C>]
rcvd [LCP TermReq id=0x4 10 49 41 37 00 3c cd 74 00 00 08 9a]
LCP terminated by peer (^PIA7^@<M-Mt^@^@^HM-^Z)
sent [LCP TermAck id=0x4]

    

Answer 1

Encontrou o problema.

Se você especificar o domínio no arquivo chap-secrets em seu nome de usuário, a parte de autenticação será bem-sucedida, mas, por algum motivo, você receberá um texto distorcido.

Por exemplo, se você usar:

[email protected]

e você receberá um texto distorcido, use:

foo

como seu nome de usuário