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vyos-documentation/docs/configuration/vpn/sstp.rst
rebortg 19596fd91e vpn: fix lint errors
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.. _sstp:
####
SSTP
####
:abbr:`SSTP (Secure Socket Tunneling Protocol)` is a form of :abbr:`VPN
(Virtual Private Network)` tunnel that provides a mechanism to transport PPP
traffic through an SSL/TLS channel. SSL/TLS provides transport-level security
with key negotiation, encryption and traffic integrity checking. The use of
SSL/TLS over TCP port 443 allows SSTP to pass through virtually all firewalls
and proxy servers except for authenticated web proxies.
SSTP is available for Linux, BSD, and Windows.
VyOS utilizes accel-ppp_ to provide SSTP server functionality. We support both
local and RADIUS authentication.
As SSTP provides PPP via a SSL/TLS channel the use of either publically signed
certificates as well as a private PKI is required.
.. note:: All certificates should be stored on VyOS under ``/config/auth``. If
certificates are not stored in the ``/config`` directory they will not be
migrated during a software update.
Certificates
============
Self Signed CA
--------------
To generate the CA, the server private key and certificates the following
commands can be used.
.. code-block:: none
vyos@vyos:~$ mkdir -p /config/user-data/sstp
vyos@vyos:~$ openssl req -newkey rsa:4096 -new -nodes -x509 -days 3650 -keyout /config/user-data/sstp/server.key -out /config/user-data/sstp/server.crt
Generating a 4096 bit RSA private key
.........................++
...............................................................++
writing new private key to 'server.key'
[...]
Country Name (2 letter code) [AU]:
State or Province Name (full name) [Some-State]:
Locality Name (eg, city) []:
Organization Name (eg, company) [Internet Widgits Pty Ltd]:
Organizational Unit Name (eg, section) []:
Common Name (e.g. server FQDN or YOUR name) []:
Email Address []:
vyos@vyos:~$ openssl req -new -x509 -key /config/user-data/sstp/server.key -out /config/user-data/sstp/ca.crt
[...]
Country Name (2 letter code) [AU]:
State or Province Name (full name) [Some-State]:
Locality Name (eg, city) []:
Organization Name (eg, company) [Internet Widgits Pty Ltd]:
Organizational Unit Name (eg, section) []:
Common Name (e.g. server FQDN or YOUR name) []:
Email Address []:
Configuration
=============
.. cfgcmd:: set vpn sstp authentication local-users username <user> password
<pass>
Create `<user>` for local authentication on this system. The users password
will be set to `<pass>`.
.. cfgcmd:: set vpn sstp authentication local-users username <user> disable
Disable `<user>` account.
.. cfgcmd:: set vpn sstp authentication local-users username <user> static-ip
<address>
Assign static IP address to `<user>` account.
.. cfgcmd:: set vpn sstp authentication local-users username <user> rate-limit
download <bandwidth>
Download bandwidth limit in kbit/s for `<user>`.
.. cfgcmd:: set vpn sstp authentication local-users username <user> rate-limit
upload <bandwidth>
Upload bandwidth limit in kbit/s for `<user>`.
.. cfgcmd:: set vpn sstp authentication protocols
<pap | chap | mschap | mschap-v2>
Require the peer to authenticate itself using one of the following protocols:
pap, chap, mschap, mschap-v2.
.. cfgcmd:: set vpn sstp authentication mode <local | radius>
Set authentication backend. The configured authentication backend is used
for all queries.
* **radius**: All authentication queries are handled by a configured RADIUS
server.
* **local**: All authentication queries are handled locally.
.. cfgcmd:: set vpn sstp gateway-address <gateway>
Specifies single `<gateway>` IP address to be used as local address of PPP
interfaces.
.. cfgcmd:: set vpn sstp client-ip-pool subnet <subnet>
Use `<subnet>` as the IP pool for all connecting clients.
.. cfgcmd:: set vpn sstp client-ipv6-pool prefix <address> mask <number-of-bits>
Use this comand to set the IPv6 address pool from which an SSTP client
will get an IPv6 prefix of your defined length (mask) to terminate the
SSTP endpoint at their side. The mask length can be set from 48 to 128
bit long, the default value is 64.
.. cfgcmd:: set vpn sstp client-ipv6-pool delegate <address> delegation-prefix
<number-of-bits>
Use this command to configure DHCPv6 Prefix Delegation (RFC3633) on
SSTP. You will have to set your IPv6 pool and the length of the
delegation prefix. From the defined IPv6 pool you will be handing out
networks of the defined length (delegation-prefix). The length of the
delegation prefix can be set from 32 to 64 bit long.
.. cfgcmd:: set vpn sstp name-server <address>
Connected client should use `<address>` as their DNS server. This
command accepts both IPv4 and IPv6 addresses. Up to two nameservers
can be configured for IPv4, up to three for IPv6.
Maximum number of IPv4 nameservers
SSL Certificates
----------------
.. cfgcmd:: set vpn sstp ssl ca-cert-file <file>
Path to `<file>` pointing to the certificate authority certificate.
.. cfgcmd:: set vpn sstp ssl cert-file <file>
Path to `<file>` pointing to the servers certificate (public portion).
.. cfgcmd:: set vpn sstp ssl key-file <file>
Path to `<file>` pointing to the servers certificate (private portion).
PPP Settings
------------
.. cfgcmd:: set vpn sstp ppp-options lcp-echo-failure <number>
Defines the maximum `<number>` of unanswered echo requests. Upon reaching the
value `<number>`, the session will be reset.
.. cfgcmd:: set vpn sstp ppp-options lcp-echo-interval <interval>
If this option is specified and is greater than 0, then the PPP module will
send LCP pings of the echo request every `<interval>` seconds.
.. cfgcmd:: set vpn sstp ppp-options lcp-echo-timeout
Specifies timeout in seconds to wait for any peer activity. If this option
specified it turns on adaptive lcp echo functionality and "lcp-echo-failure"
is not used.
.. cfgcmd:: set vpn sstp ppp-options mppe <require | prefer | deny>
Specifies :abbr:`MPPE (Microsoft Point-to-Point Encryption)` negotioation
preference.
* **require** - ask client for mppe, if it rejects drop connection
* **prefer** - ask client for mppe, if it rejects don't fail
* **deny** - deny mppe
Default behavior - don't ask client for mppe, but allow it if client wants.
Please note that RADIUS may override this option by MS-MPPE-Encryption-Policy
attribute.
RADIUS
------
Server
^^^^^^
.. cfgcmd:: set vpn sstp authentication radius server <server> port <port>
Configure RADIUS `<server>` and its required port for authentication requests.
.. cfgcmd:: set vpn sstp authentication radius server <server> key <secret>
Configure RADIUS `<server>` and its required shared `<secret>` for
communicating with the RADIUS server.
.. cfgcmd:: set vpn sstp authentication radius server <server> fail-time <time>
Mark RADIUS server as offline for this given `<time>` in seconds.
.. cfgcmd:: set vpn sstp authentication radius server <server> disable
Temporary disable this RADIUS server.
Options
^^^^^^^
.. cfgcmd:: set vpn sstp authentication radius acct-timeout <timeout>
Timeout to wait reply for Interim-Update packets. (default 3 seconds)
.. cfgcmd:: set vpn sstp authentication radius dynamic-author server <address>
Specifies IP address for Dynamic Authorization Extension server (DM/CoA)
.. cfgcmd:: set vpn sstp authentication radius dynamic-author port <port>
Port for Dynamic Authorization Extension server (DM/CoA)
.. cfgcmd:: set vpn sstp authentication radius dynamic-author key <secret>
Secret for Dynamic Authorization Extension server (DM/CoA)
.. cfgcmd:: set vpn sstp authentication radius max-try <number>
Maximum number of tries to send Access-Request/Accounting-Request queries
.. cfgcmd:: set vpn sstp authentication radius timeout <timeout>
Timeout to wait response from server (seconds)
.. cfgcmd:: set vpn sstp authentication radius nas-identifier <identifier>
Value to send to RADIUS server in NAS-Identifier attribute and to be matched
in DM/CoA requests.
.. cfgcmd:: set vpn sstp authentication radius nas-ip-address <address>
Value to send to RADIUS server in NAS-IP-Address attribute and to be matched
in DM/CoA requests. Also DM/CoA server will bind to that address.
.. cfgcmd:: set vpn sstp authentication radius source-address <address>
Source IPv4 address used in all RADIUS server queires.
.. cfgcmd:: set vpn sstp authentication radius rate-limit attribute <attribute>
Specifies which RADIUS server attribute contains the rate limit information.
The default attribute is `Filter-Id`.
.. cfgcmd:: set vpn sstp authentication radius rate-limit enable
Enables bandwidth shaping via RADIUS.
.. cfgcmd:: set vpn sstp authentication radius rate-limit vendor
Specifies the vendor dictionary, dictionary needs to be in
/usr/share/accel-ppp/radius.
Example
=======
* Use local user `foo` with password `bar`
* Client IP addresses will be provided from pool `192.0.2.0/25`
.. code-block:: none
set vpn sstp authentication local-users username vyos password vyos
set vpn sstp authentication mode local
set vpn sstp gateway-address 192.0.2.254
set vpn sstp client-ip-pool subnet 192.0.2.0/25
set vpn sstp name-server 10.0.0.1
set vpn sstp name-server 10.0.0.2
set vpn sstp ssl ca-cert-file /config/auth/ca.crt
set vpn sstp ssl cert-file /config/auth/server.crt
set vpn sstp ssl key-file /config/auth/server.key
Testing SSTP
============
Once you have setup your SSTP server there comes the time to do some basic
testing. The Linux client used for testing is called sstpc_. sstpc_ requires a
PPP configuration/peer file.
The following PPP configuration tests MSCHAP-v2:
.. code-block:: none
$ cat /etc/ppp/peers/vyos
usepeerdns
#require-mppe
#require-pap
require-mschap-v2
noauth
lock
refuse-pap
refuse-eap
refuse-chap
refuse-mschap
#refuse-mschap-v2
nobsdcomp
nodeflate
debug
You can now "dial" the peer with the follwoing command: ``sstpc --log-level 4
--log-stderr --user vyos --password vyos vpn.example.com -- call vyos``.
A connection attempt will be shown as:
.. code-block:: none
$ sstpc --log-level 4 --log-stderr --user vyos --password vyos vpn.example.com -- call vyos
Mar 22 13:29:12 sstpc[12344]: Resolved vpn.example.com to 192.0.2.1
Mar 22 13:29:12 sstpc[12344]: Connected to vpn.example.com
Mar 22 13:29:12 sstpc[12344]: Sending Connect-Request Message
Mar 22 13:29:12 sstpc[12344]: SEND SSTP CRTL PKT(14)
Mar 22 13:29:12 sstpc[12344]: TYPE(1): CONNECT REQUEST, ATTR(1):
Mar 22 13:29:12 sstpc[12344]: ENCAP PROTO(1): 6
Mar 22 13:29:12 sstpc[12344]: RECV SSTP CRTL PKT(48)
Mar 22 13:29:12 sstpc[12344]: TYPE(2): CONNECT ACK, ATTR(1):
Mar 22 13:29:12 sstpc[12344]: CRYPTO BIND REQ(4): 40
Mar 22 13:29:12 sstpc[12344]: Started PPP Link Negotiation
Mar 22 13:29:15 sstpc[12344]: Sending Connected Message
Mar 22 13:29:15 sstpc[12344]: SEND SSTP CRTL PKT(112)
Mar 22 13:29:15 sstpc[12344]: TYPE(4): CONNECTED, ATTR(1):
Mar 22 13:29:15 sstpc[12344]: CRYPTO BIND(3): 104
Mar 22 13:29:15 sstpc[12344]: Connection Established
$ ip addr show ppp0
164: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1452 qdisc fq_codel state UNKNOWN group default qlen 3
link/ppp promiscuity 0
inet 100.64.2.2 peer 100.64.1.1/32 scope global ppp0
valid_lft forever preferred_lft forever
.. _sstpc: https://github.com/reliablehosting/sstp-client
.. include:: /_include/common-references.txt
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