Установка OpenConnect сервера в СentOS 7

Приветствую Вас, уважаемые читатели. Сегодня статья: "Установка OpenConnect сервера в СentOS 7". Произведём установку и настройку OpenConnect сервера, а так же проверим работу клиентского приложения под ОС Windows.

OpenConnect сервер – это бесплатный аналог другого продукта, под названием Cisco AnyConnect. OpenConnect – кроссплатформенное ПО. Клиентские приложения можно найти в Google Play и App Store. Клиент под Windows, можно найти на одном из ресурсов разработчиков.

Ссылка на сайт разработчиков: http://ocserv.gitlab.io/www/manual.html

Ссылка на проект с приложением под Windows: https://openconnect.github.io/openconnect-gui/

Установка сервера OpenConnect

• Для установки Ocserv, в системе должен быть подключен репозиторий epel-release. Если он не подключён, то подключаем его.

# yum install epel-release

• После подключения нужного репозитория, производим установку Ocserv, и необходимых утилит.

# yum install ocserv gnutls-utils

• Следующим шагом, создаём директорию, в которой будем производить манипуляции с ключами и сертификатами.

# mkdir /etc/ocserv/cert

• Заходим в созданную директорию /etc/ocserv/cert/.

# cd /etc/ocserv/cert/

• Создаём файл /etc/ocserv/cert/ca.tmpl с регистрационными данными для сертификационного центра. Регистрационные данные можно изменить на свои.

cn = "My CN"
organization = "CN"
serial = 1
expiration_days = -1
ca
signing_key
cert_signing_key
crl_signing_key

• Выполняем команды для создания ключа ca-key.pem, и сертификата ca-cert.pem сертификационного центра.

# certtool --generate-privkey --outfile ca-key.pem
# certtool --generate-self-signed --load-privkey ca-key.pem --template ca.tmpl --outfile ca-cert.pem

• Создаём файл /etc/ocserv/server.tmpl с регистрационными данными сервера. Регистрационные данные можно изменить на свои.

cn = "MY CN"
dns_name = "my.cnnn"
organization = "My cn"
expiration_days = -1
signing_key
encryption_key
tls_www_server

• Выполняем команды для создания ключа server-key.pem, и сертификата server-cert.pem для VPN-сервера.

# certtool --generate-privkey --outfile server-key.pem
# certtool --generate-certificate --load-privkey server-key.pem --load-ca-certificate ca-cert.pem --load-ca-privkey ca-key.pem --template /etc/ocserv/server.tmpl --outfile server-cert.pem

• Создаём директорию, в которой будут собраны ключи и сертификаты.

# mkdir /etc/ocserv/ssl/

• Возвращаемся в директорию /etc/ocserv/cert/, и копируем нужные файла в директорию /etc/ocserv/ssl/.

# cd /etc/ocserv/cert/
# cp ca-cert.pem server-key.pem server-cert.pem /etc/ocserv/ssl/

Конфигурация OpenConnect сервера

• Находим файл /etc/ocserv/ocserv.conf, этот файл отвечает за конфигурацию сервера, и производим в нём некоторые изменения.

• Сначала нужно настроить аутентификацию. Для этого нам нужно отключить метод аутентификации по умолчанию, настроить свой метод аутентификации, и указать пути расположения необходимых файлов.

 Закомментировать строчку
 auth = "pam"

 Раскомментировать строчку
 auth = "plain[passwd=/etc/ocserv/sample.passwd,otp=./sample.otp]"
 И заменить её на строчку
 auth = "plain[passwd=/etc/ocserv/passwd]"

 Две строчки 
 server-cert = /etc/pki/ocserv/public/server.crt
 server-key = /etc/pki/ocserv/private/server.key
 Заменить на три строчки
 server-cert = /etc/ocserv/ssl/server-cert.pem
 server-key = /etc/ocserv/ssl/server-key.pem
 ca-cert = /etc/ocserv/ssl/ca-cert.pem

• Следующим шагом, укажем подсеть для нашей VPN. Для этого раскомментируем нужную строчку.

# ipv4-network = 192.168.1.0/24

• Сервер по умолчанию работает на 443 порту. Отключим режим работы по UDP, чтобы сервер был ещё менее заметен в потоке трафика.

Удаляем строчку
 udp-port = 443

• Напоследок - добавляем Dns-сервера в конце файла. Можете прописать какие-угодно.

dns = 8.8.8.8
dns = 4.2.2.4

• Готовый конфиг с дополнительными надстройками:

### The following directives do not change with server reload.
#
# User authentication method. To require multiple methods to be
# used for the user to login, add multiple auth directives. The values
# in the 'auth' directive are AND composed (if multiple all must
# succeed).
# Available options: certificate, plain, pam, radius, gssapi.
# Note that authentication methods utilizing passwords cannot be
# combined (e.g., the plain, pam or radius methods).
#
# certificate:
#  This indicates that all connecting users must present a certificate.
#  The username and user group will be then extracted from it (see
#  cert-user-oid and cert-group-oid). The certificate to be accepted
#  it must be signed by the CA certificate as specified in 'ca-cert' and
#  it must not be listed in the CRL, as specified by the 'crl' option.
#
# pam[gid-min=1000]:
#  This enabled PAM authentication of the user. The gid-min option is used 
# by auto-select-group option, in order to select the minimum valid group ID.
#
# plain[passwd=/etc/ocserv/ocpasswd,otp=/etc/ocserv/users.otp]
#  The plain option requires specifying a password file which contains
# entries of the following format.
# "username:groupname1,groupname2:encoded-password"
# One entry must be listed per line, and 'ocpasswd' should be used
# to generate password entries. The 'otp' suboption allows to specify
# an oath password file to be used for one time passwords; the format of
# the file is described in https://code.google.com/p/mod-authn-otp/wiki/UsersFile
#
# radius[config=/etc/radiusclient/radiusclient.conf,groupconfig=true,nas-identifier=name,override-interim-updates=false]:
#  The radius option requires specifying freeradius-client configuration
# file. If the groupconfig option is set, then config-per-user will be overriden,
# and all configuration will be read from radius. The 'override-interim-updates' if set to
# true will ignore Acct-Interim-Interval from the server and 'stats-report-time' will be considered.
#
# gssapi[keytab=/etc/key.tab,require-local-user-map=true,tgt-freshness-time=900]
#  The gssapi option allows to use authentication methods supported by GSSAPI,
# such as Kerberos tickets with ocserv. It should be best used as an alternative
# to PAM (i.e., have pam in auth and gssapi in enable-auth), to allow users with
# tickets and without tickets to login. The default value for require-local-user-map
# is true. The 'tgt-freshness-time' if set, it would require the TGT tickets presented
# to have been issued within the provided number of seconds. That option is used to
# restrict logins even if the KDC provides long time TGT tickets.
#auth = "pam"
#auth = "pam[gid-min=1000]"
auth = "plain[passwd=/etc/ocserv/passwd]"
#auth = "certificate"
#auth = "radius[config=/etc/radiusclient/radiusclient.conf,groupconfig=true]"
# Specify alternative authentication methods that are sufficient
# for authentication. That is, if set, any of the methods enabled
# will be sufficient to login, irrespective of the main 'auth' entries.
# When multiple options are present, they are OR composed (any of them
# succeeding allows login).
#enable-auth = "certificate"
#enable-auth = "gssapi"
#enable-auth = "gssapi[keytab=/etc/key.tab,require-local-user-map=true,tgt-freshness-time=900]"
# Accounting methods available:
# radius: can be combined with any authentication method, it provides
#      radius accounting to available users (see also stats-report-time).
#
# pam: can be combined with any authentication method, it provides
#      a validation of the connecting user's name using PAM. It is
#      superfluous to use this method when authentication is already
#      PAM.
#
# Only one accounting method can be specified.
#acct = "radius[config=/etc/radiusclient/radiusclient.conf]"
# Use listen-host to limit to specific IPs or to the IPs of a provided 
# hostname.
#listen-host = [IP|HOSTNAME]
# When the server has a dynamic DNS address (that may change),
# should set that to true to ask the client to resolve again on
# reconnects.
#listen-host-is-dyndns = true
# TCP and UDP port number
tcp-port = 443
# Accept connections using a socket file. It accepts HTTP
# connections (i.e., without SSL/TLS unlike its TCP counterpart),
# and uses it as the primary channel. That option cannot be
# combined with certificate authentication.
#listen-clear-file = /var/run/ocserv-conn.socket
# The user the worker processes will be run as. It should be
# unique (no other services run as this user).
run-as-user = ocserv
run-as-group = ocserv
# socket file used for IPC with occtl. You only need to set that,
# if you use more than a single servers.
#occtl-socket-file = /var/run/occtl.socket
# socket file used for server IPC (worker-main), will be appended with .PID
# It must be accessible within the chroot environment (if any), so it is best
# specified relatively to the chroot directory.
socket-file = ocserv.sock
# The default server directory. Does not require any devices present.
chroot-dir = /var/lib/ocserv
### All configuration options below this line are reloaded on a SIGHUP.
### The options above, will remain unchanged. Note however, that the 
### server-cert, server-key, dh-params and ca-cert options will be reloaded
### if the provided file changes, on server reload. That allows certificate
### rotation, but requires the server key to remain the same for seamless
### operation. If the server key changes on reload, there may be connection
### failures during the reloading time.
# Whether to enable seccomp/Linux namespaces worker isolation. That restricts the number of 
# system calls allowed to a worker process, in order to reduce damage from a
# bug in the worker process. It is available on Linux systems at a performance cost.
# The performance cost is roughly 2% overhead at transfer time (tested on a Linux 3.17.8).
# Note however, that process isolation is restricted to the specific libc versions
# the isolation was tested at. If you get random failures on worker processes, try
# disabling that option and report the failures you, along with system and debugging
# information at: https://gitlab.com/ocserv/ocserv/issues
isolate-workers = true
# A banner to be displayed on clients
# banner = "Welcome to VPN"
# Limit the number of clients. Unset or set to zero for unlimited.
#max-clients = 1024
max-clients = 40
# Limit the number of identical clients (i.e., users connecting 
# multiple times). Unset or set to zero for unlimited.
max-same-clients = 1
# Limit the number of client connections to one every X milliseconds 
# (X is the provided value). Set to zero for no limit.
#rate-limit-ms = 100
# Stats report time. The number of seconds after which each
# worker process will report its usage statistics (number of
# bytes transferred etc). This is useful when accounting like
# radius is in use.
#stats-report-time = 360
# Keepalive in seconds
keepalive = 300
# Dead peer detection in seconds.
# Note that when the client is behind a NAT this value
# needs to be short enough to prevent the NAT disassociating
# his UDP session from the port number. Otherwise the client
# could have his UDP connection stalled, for several minutes.
dpd = 60
# Dead peer detection for mobile clients. That needs to
# be higher to prevent such clients being awaken too 
# often by the DPD messages, and save battery.
# The mobile clients are distinguished from the header
# 'X-AnyConnect-Identifier-DeviceType'.
mobile-dpd = 300
# If using DTLS, and no UDP traffic is received for this
# many seconds, attempt to send future traffic over the TCP
# connection instead, in an attempt to wake up the client
# in the case that there is a NAT and the UDP translation
# was deleted. If this is unset, do not attempt to use this
# recovery mechanism.
switch-to-tcp-timeout = 30
# MTU discovery (DPD must be enabled)
try-mtu-discovery = true
# The key and the certificates of the server
# The key may be a file, or any URL supported by GnuTLS (e.g., 
# tpmkey:uuid=xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxx;storage=user
# or pkcs11:object=my-vpn-key;object-type=private)
#
# The server-cert file may contain a single certificate, or
# a sorted certificate chain.
#
# There may be multiple server-cert and server-key directives,
# but each key should correspond to the preceding certificate.
# The certificate files will be reloaded when changed allowing for in-place
# certificate renewal (they are checked and reloaded periodically;
# a SIGHUP signal to main server will force reload).
server-cert = /etc/ocserv/ssl/server-cert.pem
server-key = /etc/ocserv/ssl/server-key.pem
# Diffie-Hellman parameters. Only needed if you require support
# for the DHE ciphersuites (by default this server supports ECDHE).
# Can be generated using:
# certtool --generate-dh-params --outfile /path/to/dh.pem
#dh-params = /path/to/dh.pem
# If you have a certificate from a CA that provides an OCSP
# service you may provide a fresh OCSP status response within
# the TLS handshake. That will prevent the client from connecting
# independently on the OCSP server.
# You can update this response periodically using:
# ocsptool --ask --load-cert=your_cert --load-issuer=your_ca --outfile response
# Make sure that you replace the following file in an atomic way.
#ocsp-response = /path/to/ocsp.der
# In case PKCS #11, TPM or encrypted keys are used the PINs should be available
# in files. The srk-pin-file is applicable to TPM keys only, and is the 
# storage root key.
#pin-file = /path/to/pin.txt
#srk-pin-file = /path/to/srkpin.txt
# The password or PIN needed to unlock the key in server-key file.
# Only needed if the file is encrypted or a PKCS #11 object. This
# is an alternative method to pin-file.
#key-pin = 1234
# The SRK PIN for TPM.
# This is an alternative method to srk-pin-file.
#srk-pin = 1234
# The Certificate Authority that will be used to verify
# client certificates (public keys) if certificate authentication
# is set.
ca-cert = /etc/ocserv/ssl/ca-cert.pem
# The object identifier that will be used to read the user ID in the client 
# certificate. The object identifier should be part of the certificate's DN
# Useful OIDs are: 
#  CN = 2.5.4.3, UID = 0.9.2342.19200300.100.1.1
cert-user-oid = 0.9.2342.19200300.100.1.1
# The object identifier that will be used to read the user group in the 
# client  certificate. The object identifier should be part of the certificate's
# DN. Useful OIDs are: 
#  OU (organizational unit) = 2.5.4.11 
#cert-group-oid = 2.5.4.11
# The revocation list of the certificates issued by the 'ca-cert' above.
# See the manual to generate an empty CRL initially. The CRL will be reloaded
# periodically when ocserv detects a change in the file. To force a reload use
# SIGHUP.
#crl = /path/to/crl.pem
# Uncomment this to enable compression negotiation (LZS, LZ4).
compression = true
# Set the minimum size under which a packet will not be compressed.
# That is to allow low-latency for VoIP packets. The default size
# is 256 bytes. Modify it if the clients typically use compression
# as well of VoIP with codecs that exceed the default value.
no-compress-limit = 256
# GnuTLS priority string; note that SSL 3.0 is disabled by default
# as there are no openconnect (and possibly anyconnect clients) using
# that protocol. The string below does not enforce perfect forward
# secrecy, in order to be compatible with legacy clients.
#
# Note that the most performant ciphersuites are the moment are the ones
# involving AES-GCM. These are very fast in x86 and x86-64 hardware, and
# in addition require no padding, thus taking full advantage of the MTU.
# For that to be taken advantage of, the openconnect client must be
# used, and the server must be compiled against GnuTLS 3.2.7 or later.
# Use "gnutls-cli --benchmark-tls-ciphers", to see the performance
# difference with AES_128_CBC_SHA1 (the default for anyconnect clients)
# in your system.
#tls-priorities = "NORMAL:%SERVER_PRECEDENCE:%COMPAT:-VERS-SSL3.0"
tls-priorities = "NORMAL:%SERVER_PRECEDENCE:%COMPAT:-VERS-SSL3.0"
# More combinations in priority strings are available, check
# http://gnutls.org/manual/html_node/Priority-Strings.html
# E.g., the string below enforces perfect forward secrecy (PFS) 
# on the main channel.
#tls-priorities = "NORMAL:%SERVER_PRECEDENCE:%COMPAT:-RSA:-VERS-SSL3.0:-ARCFOUR-128"
# That option requires the established DTLS channel to use the same
# cipher as the primary TLS channel. This cannot be combined with
# listen-clear-file since the ciphersuite information is not available
# in that configuration. Note also, that this option implies that
# dtls-legacy option is false; this option cannot be enforced
# in the legacy/compat protocol.
#match-tls-dtls-ciphers = true
# The time (in seconds) that a client is allowed to stay connected prior
# to authentication
auth-timeout = 240
# The time (in seconds) that a client is allowed to stay idle (no traffic)
# before being disconnected. Unset to disable.
idle-timeout = 1200
# The time (in seconds) that a client is allowed to stay connected
# Unset to disable.
#session-timeout = 86400
# The time (in seconds) that a mobile client is allowed to stay idle (no
# traffic) before being disconnected. Unset to disable.
mobile-idle-timeout = 1800
# The time (in seconds) that a client is not allowed to reconnect after 
# a failed authentication attempt.
min-reauth-time = 3
# Banning clients in ocserv works with a point system. IP addresses
# that get a score over that configured number are banned for
# min-reauth-time seconds. By default a wrong password attempt is 10 points,
# a KKDCP POST is 1 point, and a connection is 1 point. Note that
# due to difference processes being involved the count of points
# will not be real-time precise.
#
# Score banning cannot be reliably used when receiving proxied connections
# locally from an HTTP server (i.e., when listen-clear-file is used).
#
# Set to zero to disable.
max-ban-score = 50
# The time (in seconds) that all score kept for a client is reset.
ban-reset-time = 300
# In case you'd like to change the default points.
#ban-points-wrong-password = 10
#ban-points-connection = 1
#ban-points-kkdcp = 1
# Cookie timeout (in seconds)
# Once a client is authenticated he's provided a cookie with
# which he can reconnect. That cookie will be invalided if not
# used within this timeout value. On a user disconnection, that
# cookie will also be active for this time amount prior to be
# invalid. That should allow a reasonable amount of time for roaming
# between different networks.
cookie-timeout = 300
# If this is enabled (not recommended) the cookies will stay
# valid even after a user manually disconnects, and until they
# expire. This may improve roaming with some broken clients.
#persistent-cookies = true
# Whether roaming is allowed, i.e., if true a cookie is
# restricted to a single IP address and cannot be re-used
# from a different IP.
deny-roaming = false
# ReKey time (in seconds)
# ocserv will ask the client to refresh keys periodically once
# this amount of seconds is elapsed. Set to zero to disable (note
# that, some clients fail if rekey is disabled).
rekey-time = 172800
# ReKey method
# Valid options: ssl, new-tunnel
#  ssl: Will perform an efficient rehandshake on the channel allowing
#       a seamless connection during rekey.
#  new-tunnel: Will instruct the client to discard and re-establish the channel.
#       Use this option only if the connecting clients have issues with the ssl
#       option.
rekey-method = ssl
# Script to call when a client connects and obtains an IP.
# The following parameters are passed on the environment.
# REASON, USERNAME, GROUPNAME, HOSTNAME (the hostname selected by client), 
# DEVICE, IP_REAL (the real IP of the client), IP_REAL_LOCAL (the local
# interface IP the client connected), IP_LOCAL (the local IP
# in the P-t-P connection), IP_REMOTE (the VPN IP of the client),
# IPV6_LOCAL (the IPv6 local address if there are both IPv4 and IPv6
# assigned), IPV6_REMOTE (the IPv6 remote address), IPV6_PREFIX, and
# ID (a unique numeric ID); REASON may be "connect" or "disconnect".
# In addition the following variables OCSERV_ROUTES (the applied routes for this
# client), OCSERV_NO_ROUTES, OCSERV_DNS (the DNS servers for this client),
# will contain a space separated list of routes or DNS servers. A version
# of these variables with the 4 or 6 suffix will contain only the IPv4 or
# IPv6 values.
# The disconnect script will receive the additional values: STATS_BYTES_IN,
# STATS_BYTES_OUT, STATS_DURATION that contain a 64-bit counter of the bytes 
# output from the tun device, and the duration of the session in seconds.
#connect-script = /usr/bin/ocserv-script
#disconnect-script = /usr/bin/ocserv-script
# UTMP
# Register the connected clients to utmp. This will allow viewing
# the connected clients using the command 'who'.
#use-utmp = true
# Whether to enable support for the occtl tool (i.e., either through D-BUS,
# or via a unix socket).
use-occtl = true
# PID file. It can be overriden in the command line.
pid-file = /var/run/ocserv.pid
# Set the protocol-defined priority (SO_PRIORITY) for packets to
# be sent. That is a number from 0 to 6 with 0 being the lowest
# priority. Alternatively this can be used to set the IP Type-
# Of-Service, by setting it to a hexadecimal number (e.g., 0x20).
# This can be set per user/group or globally.
#net-priority = 3
# Set the VPN worker process into a specific cgroup. This is Linux
# specific and can be set per user/group or globally.
#cgroup = "cpuset,cpu:test"
#
# Network settings
#
# The name to use for the tun device
device = vpns
# Whether the generated IPs will be predictable, i.e., IP stays the
# same for the same user when possible.
predictable-ips = true
# The default domain to be advertised
default-domain = example.com
# The pool of addresses that leases will be given from. If the leases
# are given via Radius, or via the explicit-ip? per-user config option then 
# these network values should contain a network with at least a single
# address that will remain under the full control of ocserv (that is
# to be able to assign the local part of the tun device address).
#ipv4-network = 192.168.1.0
#ipv4-netmask = 255.255.255.0
#ipv4-network = 10.10.0.0
#ipv4-netmask = 255.255.255.0
# An alternative way of specifying the network:
ipv4-network = 192.168.1.0/24
# The IPv6 subnet that leases will be given from.
#ipv6-network = fda9:4efe:7e3b:03ea::/64
# Specify the size of the network to provide to clients. It is
# generally recommended to provide clients with a /64 network in
# IPv6, but any subnet may be specified. To provide clients only
# with a single IP use the prefix 128.
#ipv6-subnet-prefix = 128
#ipv6-subnet-prefix = 64
# Whether to tunnel all DNS queries via the VPN. This is the default
# when a default route is set.
tunnel-all-dns = true
# The advertized DNS server. Use multiple lines for
# multiple servers.
# dns = fc00::4be0
# dns = 192.168.1.2
# dns = 8.8.8.8
# dns = 8.8.4.4
dns = 1.1.1.1
dns = 1.0.0.1
# The NBNS server (if any)
#nbns = 192.168.1.3
# The domains over which the provided DNS should be used. Use
# multiple lines for multiple domains.
#split-dns = example.com
# Prior to leasing any IP from the pool ping it to verify that
# it is not in use by another (unrelated to this server) host.
# Only set to true, if there can be occupied addresses in the
# IP range for leases.
ping-leases = false
# Use this option to enforce an MTU value to the incoming
# connections. Unset to use the default MTU of the TUN device.
#mtu = 1420
# Unset to enable bandwidth restrictions (in bytes/sec). The
# setting here is global, but can also be set per user or per group.
#rx-data-per-sec = 40000
#tx-data-per-sec = 40000
# The number of packets (of MTU size) that are available in
# the output buffer. The default is low to improve latency.
# Setting it higher will improve throughput.
#output-buffer = 10
# Routes to be forwarded to the client. If you need the
# client to forward routes to the server, you may use the 
# config-per-user/group or even connect and disconnect scripts.
#
# To set the server as the default gateway for the client just
# comment out all routes from the server, or use the special keyword
# 'default'.
#route = 10.10.10.0/255.255.255.0
#route = 192.168.0.0/255.255.0.0
#route = fef4:db8:1000:1001::/64
# Subsets of the routes above that will not be routed by
# the server.
#no-route = 192.168.5.0/255.255.255.0
# If set, the script /usr/bin/ocserv-fw will be called to restrict
# the user to its allowed routes and prevent him from accessing
# any other routes. In case of defaultroute, the no-routes are restricted.
# All the routes applied by ocserv can be reverted using /usr/bin/ocserv-fw
# --removeall. This option can be set globally or in the per-user configuration.
#restrict-user-to-routes = true
# When set to true, all client's iroutes are made visible to all
# connecting clients except for the ones offering them. This option
# only makes sense if config-per-user is set.
#expose-iroutes = true
# Groups that a client is allowed to select from.
# A client may belong in multiple groups, and in certain use-cases
# it is needed to switch between them. For these cases the client can
# select prior to authentication. Add multiple entries for multiple groups.
# The group may be followed by a user-friendly name in brackets.
#select-group = group1
#select-group = group2[My special group]
# The name of the (virtual) group that if selected it would assign the user
# to its default group.
#default-select-group = DEFAULT
# Instead of specifying manually all the allowed groups, you may instruct
# ocserv to scan all available groups and include the full list.
#auto-select-group = true
# Configuration files that will be applied per user connection or
# per group. Each file name on these directories must match the username
# or the groupname.
# The options allowed in the configuration files are dns, nbns,
#  ipv?-network, ipv4-netmask, rx/tx-per-sec, iroute, route, no-route,
#  explicit-ipv4, explicit-ipv6, net-priority, deny-roaming, no-udp, 
#  user-profile, cgroup, stats-report-time, and session-timeout.
#
# Note that the 'iroute' option allows to add routes on the server
# based on a user or group. The syntax depends on the input accepted
# by the commands route-add-cmd and route-del-cmd (see below). The no-udp
# is a boolean option (e.g., no-udp = true), and will prevent a UDP session
# for that specific user or group.
#config-per-user = /etc/ocserv/config-per-user/
#config-per-group = /etc/ocserv/config-per-group/
# When config-per-xxx is specified and there is no group or user that
# matches, then utilize the following configuration.
#default-user-config = /etc/ocserv/defaults/user.conf
#default-group-config = /etc/ocserv/defaults/group.conf
# The system command to use to setup a route. %{R} will be replaced with the
# route/mask and %{D} with the (tun) device.
#
# The following example is from linux systems. %R should be something
# like 192.168.2.0/24 (the argument of iroute).
#route-add-cmd = "ip route add %{R} dev %{D}"
#route-del-cmd = "ip route delete %{R} dev %{D}"
# This option allows to forward a proxy. The special keywords '%{U}'
# and '%{G}', if present will be replaced by the username and group name.
#proxy-url = http://example.com/
#proxy-url = http://example.com/%{U}/
# This option allows you to specify a URL location where a client can
# post using MS-KKDCP, and the message will be forwarded to the provided
# KDC server. That is a translation URL between HTTP and Kerberos.
# In MIT kerberos you'll need to add in realms:
#   EXAMPLE.COM = {
#     kdc = https://ocserv.example.com/kerberos
#     http_anchors = FILE:/etc/ocserv-ca.pem
#   }
# This option is available if ocserv is compiled with GSSAPI support. 
#kkdcp = SERVER-PATH KERBEROS-REALM PROTOCOL@SERVER:PORT
#kkdcp = /kerberos EXAMPLE.COM udp@127.0.0.1:88
#kkdcp = /kerberos-tcp EXAMPLE.COM tcp@127.0.0.1:88
#
# The following options are for (experimental) AnyConnect client 
# compatibility. 
# This option will enable the pre-draft-DTLS version of DTLS, and
# will not require clients to present their certificate on every TLS
# connection. It must be set to true to support legacy CISCO clients
# and openconnect clients < 7.08. When set to true, it implies dtls-legacy = true.
cisco-client-compat = true
# This option allows to disable the DTLS-PSK negotiation (enabled by default).
# The DTLS-PSK negotiation was introduced in ocserv 0.11.5 to deprecate
# the pre-draft-DTLS negotiation inherited from AnyConnect. It allows the
# DTLS channel to negotiate its ciphers and the DTLS protocol version.
#dtls-psk = false
# This option allows to disable the legacy DTLS negotiation (enabled by default,
# but that may change in the future).
# The legacy DTLS uses a pre-draft version of the DTLS protocol and was
# from AnyConnect protocol. It has several limitations, that are addressed
# by the dtls-psk protocol supported by openconnect 7.08+.
dtls-legacy = true
# Client profile xml. A sample file exists in doc/profile.xml.
# It is required by some of the CISCO clients.
# This file must be accessible from inside the worker's chroot. 
user-profile = profile.xml
#Advanced options
# Option to allow sending arbitrary custom headers to the client after
# authentication and prior to VPN tunnel establishment. You shouldn't
# need to use this option normally; if you do and you think that
# this may help others, please send your settings and reason to
# the openconnect mailing list. The special keywords '%{U}'
# and '%{G}', if present will be replaced by the username and group name.
#custom-header = "X-My-Header: hi there"

• На этом с конфигурационным файлом мы закончили. Нужно включить маршрутизацию в системе. Для этого в файле /etc/sysctl.conf добавляем одну строчку.

# net.ipv4.ip_forward = 1

Перечитываем изменения.

# sysctl -p

Создание пользователей в OpenConnect Vpn

• В конфигурационном файле сервера, мы настроили аутентификацию по логину и паролю. Кроме того, мы указали файл в котором будут находится эти данные. Пришло время создать данный файл.

# touch /etc/ocserv/passwd

• Файл готов, и теперь можно создать первого пользователя.
• Для примера я создам пользователя user в группе default.

# ocpasswd -c /etc/ocserv/passwd -g default user

• Пользователю необходимо будет создать пароль.

• Со стороны сервера, все настройки закончены. Можно запускать сервер, и добавлять его в автозагрузку.

# systemctl start ocserv
# systemctl enable ocserv

• Проверяем статус OpenConnect сервера.

# systemctl status ocserv

Настройка Firewall для работы OpenConnect сервера

• Если всё в норме, то можно переходить к последнему шагу, настройке Firewall.
• Вот команды для iptables. Во втором правиле, не забудьте указать ip-адрес Вашего сервера

# iptables -I INPUT -p tcp --dport 443 -m state --state NEW -j ACCEPT
# iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -j SNAT --to-source ip_адрес_сервера
# iptables -A FORWARD -s 192.168.1.0/24 -j ACCEPT
# iptables -A FORWARD -p all -m state --state ESTABLISHED,RELATED -j ACCEPT 
# /sbin/iptables-save > /etc/sysconfig/iptables

• А можно запустить скрипт с этими правилами, и дополнительными настройками. Не забудьте указать IP_АДРЕС_ВАШЕГО_СЕРВЕРА.

#!/bin/sh
export IF_EXT="eth0"
export IPT="/sbin/iptables"
export IPT6="/sbin/ip6tables"
# Очистка всех цепочек iptables
$IPT -F
$IPT -F -t nat
$IPT -F -t mangle
$IPT -X
$IPT -t nat -X
$IPT -t mangle -X
$IPT6 --flush
# loopback
$IPT -A INPUT -i lo -j ACCEPT
$IPT -A OUTPUT -o lo -j ACCEPT
# default
$IPT -P INPUT DROP
$IPT -P OUTPUT DROP
$IPT -P FORWARD DROP
$IPT6 -P INPUT DROP
$IPT6 -P OUTPUT DROP
$IPT6 -P FORWARD DROP
# allow forwarding
echo 1 > /proc/sys/net/ipv4/ip_forward
# NAT
# #########################################
# SNAT - local users to out internet
$IPT -t nat -A POSTROUTING -s 192.168.1.0/24 -j SNAT --to-source IP_АДРЕС_ВАШЕГО_СЕРВЕРА
$IPT -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
$IPT -A INPUT -p tcp ! --syn -m state --state NEW -j DROP
$IPT -A OUTPUT -p tcp ! --syn -m state --state NEW -j DROP
# INPUT chain
# #########################################
$IPT -A INPUT -m state --state INVALID -j DROP
$IPT -A FORWARD -m state --state INVALID -j DROP
$IPT -A INPUT -p tcp --tcp-flags ALL NONE -j DROP
$IPT -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPT -A INPUT -i $IF_EXT -p tcp --dport 22 -j ACCEPT
$IPT -A INPUT -i $IF_EXT -p tcp --dport 443 -j ACCEPT
# FORWARD chain
# #########################################
$IPT -A FORWARD -s 192.168.1.0/24 -j ACCEPT
$IPT -A FORWARD -p all -m state --state ESTABLISHED,RELATED -j ACCEPT
# OUTPUT chain
# #########################################
$IPT -A OUTPUT -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT
# Записываем правила
/sbin/iptables-save > /etc/sysconfig/iptables

• Перезапускаем iptables.

# systemctl restart iptables

• Вот команды для firewalld:

# firewall-cmd --zone=public --permanent --add-port=443/tcp
# firewall-cmd --zone=public --permanent --add-masquerade

• Перезапускаем firewalld:

# systemctl reload firewalld

Подключение к OpenConnect серверу при помощи клиентского приложения

• Пришло время пробовать подключиться к OpenConnect серверу клиентским приложением.
• Я буду производить подключение в ОС Windows.
• Запускаем программу, жмём на шестерёнку, и выбираем «New profile».

• Открывается окно для ввода данных сервера, к которому нужно подключиться.

• После ввода необходимых данных, становятся активными кнопки «Save» и «Save & Connect».
• Если нажать на «Save», то профиль подключения будет просто сохранён. При нажатии на вторую кнопку - будет произведено сохранение профиля, и подключение к желаемому серверу.

• Зайдя в редактирование профиля, можно изменить параметры профиля на своё усмотрение.

• При подключении к серверу, нужно будет вводить данные: пользователь и пароль.
• Если всё сделано правильно, и произошло подключение к удалённому серверу OpenConnect, то окно программы меняется на режим «Connect».

Сегодня мы рассмотрели тему: "Установка OpenConnect сервера в СentOS 7". Установили и настроили сервер, а так же произвели подключение программой клиентом. Смотрите так же видео по теме.

Надеюсь статья была вам полезна. До встречи в новых статьях.

✍

С уважением, Андрей Бондаренко.

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Видео на тему "Установка OpenConnect сервера в СentOS 7":