openVPNは接続しますが、ほとんどの場合機能しません（RTNETLINKの回答：ファイルが存在します）
最近openVPNサーバーを作成しましたが、時々（elementryOSでopenVPNを使用して）接続してインターネットに問題なくアクセスできますが、ほとんどの時間は接続しますが、WebサイトにアクセスしようとするとDNSエラーが発生します。
私の友人は、tunnelblickを使用してMacから完全に接続できます。
私がそれを開始し、それがうまくいかないとき、私はこの出力を得ます：
root@cclient:~# openvpn --config /home/user/vpn/client.ovpn
Thu Aug 11 09:40:30 2016 OpenVPN 2.3.2 x86_64-pc-linux-gnu [SSL (OpenSSL)] [LZO] [EPOLL] [PKCS11] [eurephia] [MH] [IPv6] built on Dec 1 2014
Thu Aug 11 09:40:30 2016 Control Channel Authentication: tls-auth using INLINE static key file
Thu Aug 11 09:40:30 2016 Outgoing Control Channel Authentication: Using 160 bit message hash 'SHA1' for HMAC authentication
Thu Aug 11 09:40:30 2016 Incoming Control Channel Authentication: Using 160 bit message hash 'SHA1' for HMAC authentication
Thu Aug 11 09:40:30 2016 Socket Buffers: R=[212992->131072] S=[212992->131072]
Thu Aug 11 09:40:30 2016 NOTE: UID/GID downgrade will be delayed because of --client, --pull, or --up-delay
Thu Aug 11 09:40:30 2016 UDPv4 link local: [undef]
Thu Aug 11 09:40:30 2016 UDPv4 link remote: [AF_INET]99.139.69.XX:1194
Thu Aug 11 09:40:30 2016 TLS: Initial packet from [AF_INET]99.139.69.94:1194, sid=dcc35439 e95aefe1
Thu Aug 11 09:40:30 2016 VERIFY OK: depth=1, C=US, ST=CA, L=SanFrancisco, O=Marvin, OU=MyOrganizationalUnit, CN=Marvin CA, name=server, [email protected]
Thu Aug 11 09:40:30 2016 Validating certificate key usage
Thu Aug 11 09:40:30 2016 ++ Certificate has key usage 00a0, expects 00a0
Thu Aug 11 09:40:30 2016 VERIFY KU OK
Thu Aug 11 09:40:30 2016 Validating certificate extended key usage
Thu Aug 11 09:40:30 2016 ++ Certificate has EKU (str) TLS Web Server Authentication, expects TLS Web Server Authentication
Thu Aug 11 09:40:30 2016 VERIFY EKU OK
Thu Aug 11 09:40:30 2016 VERIFY OK: depth=0, C=US, ST=CA, L=SanFrancisco, O=Marvin, OU=MyOrganizationalUnit, CN=server, name=server, [email protected]
Thu Aug 11 09:40:30 2016 Data Channel Encrypt: Cipher 'BF-CBC' initialized with 128 bit key
Thu Aug 11 09:40:30 2016 Data Channel Encrypt: Using 160 bit message hash 'SHA1' for HMAC authentication
Thu Aug 11 09:40:30 2016 Data Channel Decrypt: Cipher 'BF-CBC' initialized with 128 bit key
Thu Aug 11 09:40:30 2016 Data Channel Decrypt: Using 160 bit message hash 'SHA1' for HMAC authentication
Thu Aug 11 09:40:30 2016 Control Channel: TLSv1, cipher TLSv1/SSLv3 DHE-RSA-AES256-SHA, 2048 bit RSA
Thu Aug 11 09:40:30 2016 [server] Peer Connection Initiated with [AF_INET]99.139.69.94:1194
Thu Aug 11 09:40:32 2016 SENT CONTROL [server]: 'Push_REQUEST' (status=1)
Thu Aug 11 09:40:32 2016 Push: Received control message: 'Push_REPLY,redirect-gateway def1 bypass-dhcp,dhcp-option DNS 208.67.222.222,dhcp-option DNS 208.67.220.220,route 10.8.0.1,topology net30,ping 10,ping-restart 120,ifconfig 10.8.0.10 10.8.0.9'
Thu Aug 11 09:40:32 2016 OPTIONS IMPORT: timers and/or timeouts modified
Thu Aug 11 09:40:32 2016 OPTIONS IMPORT: --ifconfig/up options modified
Thu Aug 11 09:40:32 2016 OPTIONS IMPORT: route options modified
Thu Aug 11 09:40:32 2016 OPTIONS IMPORT: --ip-win32 and/or --dhcp-option options modified
Thu Aug 11 09:40:32 2016 ROUTE_GATEWAY 10.245.243.254/255.255.252.0 IFACE=wlan0 HWADDR=b4:6d:83:25:c7:95
Thu Aug 11 09:40:32 2016 TUN/TAP device tun0 opened
Thu Aug 11 09:40:32 2016 TUN/TAP TX queue length set to 100
Thu Aug 11 09:40:32 2016 do_ifconfig, tt->ipv6=0, tt->did_ifconfig_ipv6_setup=0
Thu Aug 11 09:40:32 2016 /sbin/ip link set dev tun0 up mtu 1500
Thu Aug 11 09:40:32 2016 /sbin/ip addr add dev tun0 local 10.8.0.10 peer 10.8.0.9
Thu Aug 11 09:40:32 2016 /sbin/ip route add 99.139.69.XX/32 via 10.245.XXX.254
RTNETLINK answers: File exists
Thu Aug 11 09:40:32 2016 ERROR: Linux route add command failed: external program exited with error status: 2
Thu Aug 11 09:40:32 2016 /sbin/ip route add 0.0.0.0/1 via 10.8.0.9
Thu Aug 11 09:40:32 2016 /sbin/ip route add 128.0.0.0/1 via 10.8.0.9
Thu Aug 11 09:40:32 2016 /sbin/ip route add 10.8.0.1/32 via 10.8.0.9
Thu Aug 11 09:40:32 2016 GID set to nogroup
Thu Aug 11 09:40:32 2016 UID set to nobody
Thu Aug 11 09:40:32 2016 Initialization Sequence Completed
次に^ Cを押すと、
Thu Aug 11 09:44:57 2016 event_wait : Interrupted system call (code=4)
Thu Aug 11 09:44:57 2016 /sbin/ip route del 10.8.0.1/32
RTNETLINK answers: Operation not permitted
Thu Aug 11 09:44:57 2016 ERROR: Linux route delete command failed: external program exited with error status: 2
Thu Aug 11 09:44:57 2016 /sbin/ip route del 99.139.69.94/32
RTNETLINK answers: Operation not permitted
Thu Aug 11 09:44:57 2016 ERROR: Linux route delete command failed: external program exited with error status: 2
Thu Aug 11 09:44:57 2016 /sbin/ip route del 0.0.0.0/1
RTNETLINK answers: Operation not permitted
Thu Aug 11 09:44:57 2016 ERROR: Linux route delete command failed: external program exited with error status: 2
Thu Aug 11 09:44:57 2016 /sbin/ip route del 128.0.0.0/1
RTNETLINK answers: Operation not permitted
Thu Aug 11 09:44:57 2016 ERROR: Linux route delete command failed: external program exited with error status: 2
Thu Aug 11 09:44:57 2016 Closing TUN/TAP interface
Thu Aug 11 09:44:57 2016 /sbin/ip addr del dev tun0 local 10.8.0.10 peer 10.8.0.9
RTNETLINK answers: Operation not permitted
Thu Aug 11 09:44:57 2016 Linux ip addr del failed: external program exited with error status: 2
Thu Aug 11 09:44:57 2016 SIGINT[hard,] received, process exiting
これは私のclient.ovpnです
##############################################
# Sample client-side OpenVPN 2.0 config file #
# for connecting to multi-client server. #
# #
# This configuration can be used by multiple #
# clients, however each client should have #
# its own cert and key files. #
# #
# On Windows, you might want to rename this #
# file so it has a .ovpn extension #
##############################################
# Specify that we are a client and that we
# will be pulling certain config file directives
# from the server.
client
# Use the same setting as you are using on
# the server.
# On most systems, the VPN will not function
# unless you partially or fully disable
# the firewall for the TUN/TAP interface.
;dev tap
dev tun
# Windows needs the TAP-Win32 adapter name
# from the Network Connections panel
# if you have more than one. On XP SP2,
# you may need to disable the firewall
# for the TAP adapter.
;dev-node MyTap
# Are we connecting to a TCP or
# UDP server? Use the same setting as
# on the server.
;proto tcp
proto udp
# The hostname/IP and port of the server.
# You can have multiple remote entries
# to load balance between the servers.
remote 99.139.69.XX 1194
;remote my-server-2 1194
# Choose a random Host from the remote
# list for load-balancing. Otherwise
# try hosts in the order specified.
;remote-random
# Keep trying indefinitely to resolve the
# Host name of the OpenVPN server. Very useful
# on machines which are not permanently connected
# to the internet such as laptops.
resolv-retry infinite
# Most clients don't need to bind to
# a specific local port number.
nobind
# Downgrade privileges after initialization (non-Windows only)
user nobody
group nogroup
# Try to preserve some state across restarts.
persist-key
persist-tun
# If you are connecting through an
# HTTP proxy to reach the actual OpenVPN
# server, put the proxy server/IP and
# port number here. See the man page
# if your proxy server requires
# authentication.
;http-proxy-retry # retry on connection failures
;http-proxy [proxy server] [proxy port #]
# Wireless networks often produce a lot
# of duplicate packets. Set this flag
# to silence duplicate packet warnings.
;mute-replay-warnings
# SSL/TLS parms.
# See the server config file for more
# description. It's best to use
# a separate .crt/.key file pair
# for each client. A single ca
# file can be used for all clients.
#ca ca.crt
#cert client.crt
#key client.key
key-direction 1
# Verify server certificate by checking that the
# certicate has the correct key usage set.
# This is an important precaution to protect against
# a potential attack discussed here:
# http://openvpn.net/howto.html#mitm
#
# To use this feature, you will need to generate
# your server certificates with the keyUsage set to
# digitalSignature, keyEncipherment
# and the extendedKeyUsage to
# serverAuth
# EasyRSA can do this for you.
remote-cert-tls server
# If a tls-auth key is used on the server
# then every client must also have the key.
;tls-auth ta.key 1
# Select a cryptographic cipher.
# If the cipher option is used on the server
# then you must also specify it here.
;cipher x
# Enable compression on the VPN link.
# Don't enable this unless it is also
# enabled in the server config file.
comp-lzo
# Set log file verbosity.
verb 3
# Silence repeating messages
;mute 20
<ca>
-----BEGIN CERTIFICATE-----
-----END CERTIFICATE-----
</ca>
<cert>
Certificate:
Data:
Version: 3 (0x2)
Serial Number: 4 (0x4)
Signature Algorithm: sha256WithRSAEncryption
Issuer: C=US, ST=CA, L=SanFrancisco, O=Marvin, OU=MyOrganizationalUnit, CN=Marvin CA/name=server/[email protected]
Validity
Not Before: Aug 7 20:11:38 2016 GMT
Not After : Aug 5 20:11:38 2026 GMT
Subject: C=US, ST=CA, L=SanFrancisco, O=Marvin, OU=MyOrganizationalUnit, CN=theo/name=server/[email protected]
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:
Exponent: 65537 (0x10001)
X509v3 extensions:
X509v3 Basic Constraints:
CA:FALSE
Netscape Comment:
Easy-RSA Generated Certificate
X509v3 Subject Key Identifier:
X509v3 Authority Key Identifier:
keyid:
DirName:/C=US/ST=CA/L=SanFrancisco/O=Marvin/OU=MyOrganizationalUnit/CN=Marvin CA/name=server/[email protected]
serial:
X509v3 Extended Key Usage:
TLS Web Client Authentication
X509v3 Key Usage:
Digital Signature
X509v3 Subject Alternative Name:
DNS:client
Signature Algorithm: sha256WithRSAEncryption
<STUFF HERE>
-----BEGIN CERTIFICATE-----
-----END CERTIFICATE-----
</cert>
<key>
-----BEGIN PRIVATE KEY-----
-----END PRIVATE KEY-----
</key>
<tls-auth>
#
# 2048 bit OpenVPN static key
#
-----BEGIN OpenVPN Static key V1-----
-----END OpenVPN Static key V1-----
</tls-auth>
だから、DHCP設定などをプッシュしていないことに気付きました。クライアントOVPNに次の行を追加してみてください：Push "dhcp-option DNS 8.8.8.8" Push "dhcp-option DNS 8.8.4.4"
これにより、これらのDNSサーバーが使用されます（これらのアドレスはGoogleのDNSサーバーです。ネットワークにDNSサーバーが既にある場合は、そのIPアドレスを使用してください。）OpenVPNの過去の設定では、これを長い間ガイドとして使用しました以前は、OVPNのセットアップ方法に関する追加の洞察を提供できる可能性があります。
これは特権の問題のようです。回避策として、client.ovpnの権限をダウングレードできます。
/home/user/vpn/client.ovpnをエディター（nano/vim/emacs/geditなど）で開き、user行とgroup行のコメントを解除します。
これから行を変更します。
# Downgrade privileges after initialization (non-Windows only)
;user nobody
;group nogroup
これに：
# Downgrade privileges after initialization (non-Windows only)
user nobody
group nogroup