openvpn AVISO: Nenhum método de verificação de certificado do servidor foi ativado

Eu tentei instalar o openvpn no debian squeez (servidor) e conectar no meu fedora 17 como (cliente). Aqui está minha configuração:

configuração do servidor

# Server TCP
proto tcp
port 1194
dev tun

# Keys and certificates
ca /etc/openvpn/easy-rsa/keys/ca.crt
cert /etc/openvpn/easy-rsa/keys/server.crt
key /etc/openvpn/easy-rsa/keys/server.key
dh /etc/openvpn/easy-rsa/keys/dh1024.pem

# Network
# Virtual address of the VPN network
server 192.170.70.0 255.255.255.0
# This line adds the client to the router network server
push "route 192.168.1.0 255.255.255.0"
# Create a route server to the tun interface
#route 192.170.70.0 255.255.255.0

# Security
keepalive 10 120
# type of data encryption
cipher AES-128-CBC
# enabling compression
comp-lzo
# maximum number of clients allowed
max-clients 10
# no user and group specific to the use of the VPN
user nobody
group nogroup

# to make persistent connection
persist-key
persist-tun

# Log of the OpenVPN status
status /var/log/openvpn-status.log

# logs openvpnlog /var/log/openvpn.log
log-append /var/log/openvpn.log

# verbosity
verb 5

configuração do cliente

client
dev tun
proto tcp-client
remote <my server wan IP> 1194
resolv-retry infinite
cipher AES-128-CBC

# Keys
ca ca.crt
cert client.crt
key client.key

# Security
nobind
persist-key
persist-tun
comp-lzo
verb 3

Mensagem do cliente host (fedora 17) no arquivo de log /var/log/messages:

Dec  6 21:56:00 GlobalTIC NetworkManager[691]: <info> Starting VPN service 'openvpn'...
Dec  6 21:56:00 GlobalTIC NetworkManager[691]: <info> VPN service 'openvpn' started (org.freedesktop.NetworkManager.openvpn), PID 7470
Dec  6 21:56:00 GlobalTIC NetworkManager[691]: <info> VPN service 'openvpn' appeared; activating connections
Dec  6 21:56:00 GlobalTIC NetworkManager[691]: <info> VPN plugin state changed: starting (3)
Dec  6 21:56:01 GlobalTIC NetworkManager[691]: <info> VPN connection 'Connexion VPN 1' (Connect) reply received.
Dec  6 21:56:01 GlobalTIC nm-openvpn[7472]: OpenVPN 2.2.2 x86_64-redhat-linux-gnu [SSL] [LZO2] [EPOLL] [PKCS11] [eurephia] built on Sep  5 2012
Dec  6 21:56:01 GlobalTIC nm-openvpn[7472]:[COLOR="Red"][U][B] WARNING: No server certificate verification method has been enabled.[/B][/U][/COLOR]  See http://openvpn.net/howto.html#mitm for more info.
Dec  6 21:56:01 GlobalTIC nm-openvpn[7472]: NOTE: the current --script-security setting may allow this configuration to call user-defined scripts
Dec  6 21:56:01 GlobalTIC nm-openvpn[7472]:[COLOR="Red"] WARNING: file '/home/login/client/client.key' is group or others accessible[/COLOR]
Dec  6 21:56:01 GlobalTIC nm-openvpn[7472]: UDPv4 link local: [undef]
Dec  6 21:56:01 GlobalTIC nm-openvpn[7472]: UDPv4 link remote: [COLOR="Red"]<my server wan IP>[/COLOR]:1194
Dec  6 21:56:01 GlobalTIC nm-openvpn[7472]: [COLOR="Red"]read UDPv4 [ECONNREFUSED]: Connection refused (code=111)[/COLOR]
Dec  6 21:56:03 GlobalTIC nm-openvpn[7472]: [COLOR="Red"]read UDPv4[/COLOR] [ECONNREFUSED]: Connection refused (code=111)
Dec  6 21:56:07 GlobalTIC nm-openvpn[7472]: read UDPv4 [ECONNREFUSED]: Connection refused (code=111)
Dec  6 21:56:15 GlobalTIC nm-openvpn[7472]: read UDPv4 [ECONNREFUSED]: Connection refused (code=111)
Dec  6 21:56:31 GlobalTIC nm-openvpn[7472]: read UDPv4 [ECONNREFUSED]: Connection refused (code=111)
Dec  6 21:56:41 GlobalTIC NetworkManager[691]: <warn> VPN connection 'Connexion VPN 1' (IP Conf[/CODE]

ifconfig no host do servidor (debian):

ifconfig 
eth0      Link encap:Ethernet  HWaddr 08:00:27:16:21:ac  
          inet addr:192.168.1.6  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe16:21ac/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:9059 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5660 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:919427 (897.8 KiB)  TX bytes:1273891 (1.2 MiB)
tun0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          inet addr:192.170.70.1  P-t-P:192.170.70.2  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

ifconfig no host do cliente (fedora 17)

as0t0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
        inet 5.5.0.1  netmask 255.255.252.0  destination 5.5.0.1
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 200  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2  bytes 321 (321.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

as0t1: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
        inet 5.5.4.1  netmask 255.255.252.0  destination 5.5.4.1
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 200  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2  bytes 321 (321.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

as0t2: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
        inet 5.5.8.1  netmask 255.255.252.0  destination 5.5.8.1
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 200  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2  bytes 321 (321.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

as0t3: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1500
        inet 5.5.12.1  netmask 255.255.252.0  destination 5.5.12.1
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 200  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2  bytes 321 (321.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

**p255p1**: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.2  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 fe80::21d:baff:fe20:b7e6  prefixlen 64  scopeid 0x20<link>
        ether 00:1d:ba:20:b7:e6  txqueuelen 1000  (Ethernet)
        RX packets 4842070  bytes 3579798184 (3.3 GiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 3996158  bytes 2436442882 (2.2 GiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 16  

p255p1 é um rótulo para a interface eth0

e

no servidor:

root@hoteserver:/etc/openvpn# tree
.
├── client
│** ├── ca.crt
│** ├── client.conf
│** ├── client.crt
│** ├── client.csr
│** ├── client.key
│** ├── client.ovpn
│*
│** 
├── easy-rsa
│** ├── build-ca
│** ├── build-dh
│** ├── build-inter
│** ├── build-key
│** ├── build-key-pass
│** ├── build-key-pkcs12
│** ├── build-key-server
│** ├── build-req
│** ├── build-req-pass
│** ├── clean-all
│** ├── inherit-inter
│** ├── keys
│** │** ├── 01.pem
│** │** ├── 02.pem
│** │** ├── ca.crt
│** │** ├── ca.key
│** │** ├── client.crt
│** │** ├── client.csr
│** │** ├── client.key
│** │** ├── dh1024.pem
│** │** ├── index.txt
│** │** ├── index.txt.attr
│** │** ├── index.txt.attr.old
│** │** ├── index.txt.old
│** │** ├── serial
│** │** ├── serial.old
│** │** ├── server.crt
│** │** ├── server.csr
│** │** └── server.key
│** ├── list-crl
│** ├── Makefile
│** ├── openssl-0.9.6.cnf.gz
│** ├── openssl.cnf
│** ├── pkitool
│** ├── README.gz
│** ├── revoke-full
│** ├── sign-req
│** ├── vars
│** └── whichopensslcnf
├── openvpn.log
├── openvpn-status.log
├── server.conf
└── update-resolv-conf

no cliente:

[login@hoteclient openvpn]$ tree 
.
|-- easy-rsa
|   |-- 1.0
|   |   |-- build-ca
|   |   |-- build-dh
|   |   |-- build-inter
|   |   |-- build-key
|   |   |-- build-key-pass
|   |   |-- build-key-pkcs12
|   |   |-- build-key-server
|   |   |-- build-req
|   |   |-- build-req-pass
|   |   |-- clean-all
|   |   |-- list-crl
|   |   |-- make-crl
|   |   |-- openssl.cnf
|   |   |-- README
|   |   |-- revoke-crt
|   |   |-- revoke-full
|   |   |-- sign-req
|   |   `-- vars
|   `-- 2.0
|       |-- build-ca
|       |-- build-dh
|       |-- build-inter
|       |-- build-key
|       |-- build-key-pass
|       |-- build-key-pkcs12
|       |-- build-key-server
|       |-- build-req
|       |-- build-req-pass
|       |-- clean-all
|       |-- inherit-inter
|       |-- keys [error opening dir]
|       |-- list-crl
|       |-- Makefile
|       |-- openssl-0.9.6.cnf
|       |-- openssl-0.9.8.cnf
|       |-- openssl-1.0.0.cnf
|       |-- pkitool
|       |-- README
|       |-- revoke-full
|       |-- sign-req
|       |-- vars
|       `-- whichopensslcnf
|-- keys -> ./easy-rsa/2.0/keys/
`-- server.conf

É a origem do problema cipher AES-128-CBC, proto tcp-clientou UDP ou a interface p255p1em Fedora17 ou que autenticação de arquivo ta.keynão for encontrado?

Primeiro, você deve alterar as permissões no seu /home/login/client/client.keyarquivo para que ele não fique em grupo ou em outras pessoas acessíveis.

chmod 400 /home/login/client/client.key

Então, conforme descrito aqui, você deve implementar um método para verificar se seus clientes se conectam ao servidor correto e se nenhum ataque intermediário é possível.

Há uma lista completa de problemas aqui e você deve levar os avisos dados pelo OpenVPN a sério. Mas existem apenas avisos e não o motivo do seu problema para obter uma conexão. O plug-in openvpn do NetworkManager está tentando se conectar usando o UDP. Não sei qual a relação do seu client.conf com a sua configuração real do cliente. Foi usado para importar as configurações de VPN para o NetworkManager?
De qualquer forma, você deve marcar a caixa de seleção de conexão TCP na caixa de diálogo de configurações avançadas do seu perfil de conexão VPN.
Como você parece não usar tls-auth no cliente nem no servidor, não deve haver nenhum arquivo ta.key ausente (mas usar tls-auth é uma boa ideia).
A cifra parece ser a mesma nos dois lados e não deve ser um problema.
Eu realmente sugerem fortemente paraverifique o certificado do servidor , como o morlix afirmou.

Para se livrar do No server certificate verification method has been enabledaviso, gere seus certificados de cliente e servidor com a extendedKeyUsageextensão correta e adicione remote-cert-tls server-os aos do cliente openvpn.conf.

Adicione duas seções às suas autoridades de certificação openssl.cnf:

[server_cert]
basicConstraints = CA:FALSE
nsCertType = server
nsComment = "OpenSSL Generated Server Certificate"
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid,issuer:always
keyUsage = critical, digitalSignature, keyEncipherment
extendedKeyUsage = serverAuth

[client_cert]
basicConstraints = CA:FALSE
nsCertType = client, email
nsComment = "OpenSSL Generated Client Certificate"
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid,issuer
keyUsage = critical, nonRepudiation, digitalSignature, keyEncipherment
extendedKeyUsage = clientAuth, emailProtection

Assine certificados de servidor em sua CA da seguinte maneira:

openssl ca -config openssl.cnf -extensions server_cert -notext -md sha256 -in csr.pem -out cert.pem

Assine certificados de clientes como este:

openssl ca -config openssl.cnf -extensions client_cert -notext -md sha256 -in csr.pem -out cert.pem

Em seguida, no cliente, openvpn.cnfadicione a seguinte linha:

remote-cert-tls server

e reinicie o serviço openvpn.