Linux 服务器是运行在 Google Cloud 上的 Ubuntu 18.04。我按照以下优秀教程配置了 StrongSwan 服务器：
我已在 Google Cloud 中打开端口 UDP 500 和 4500，并启用了 charon 守护进程的日志记录。大多数事情似乎都按计划进行，直到我尝试从 Windows 10 VPN 连接进行连接，该连接失败并显示错误“策略匹配错误”。连接尝试失败后，charon 日志文件（级别 1）包含以下内容：
Jan 22 17:17:40 00[DMN] Starting IKE charon daemon (strongSwan 5.6.2, Linux 5.4.0-1034-gcp, x86_64)
Jan 22 17:17:40 00[CFG] PKCS11 module '<name>' lacks library path
Jan 22 17:17:40 00[CFG] disabling load-tester plugin, not configured
Jan 22 17:17:40 00[LIB] plugin 'load-tester': failed to load - load_tester_plugin_create returned NULL
Jan 22 17:17:40 00[CFG] dnscert plugin is disabled
Jan 22 17:17:40 00[CFG] ipseckey plugin is disabled
Jan 22 17:17:40 00[CFG] attr-sql plugin: database URI not set
Jan 22 17:17:40 00[CFG] loading ca certificates from '/etc/ipsec.d/cacerts'
Jan 22 17:17:40 00[CFG] loaded ca certificate "CN=VPN root CA" from '/etc/ipsec.d/cacerts/ca-cert.pem'
Jan 22 17:17:40 00[CFG] loading aa certificates from '/etc/ipsec.d/aacerts'
Jan 22 17:17:40 00[CFG] loading ocsp signer certificates from '/etc/ipsec.d/ocspcerts'
Jan 22 17:17:40 00[CFG] loading attribute certificates from '/etc/ipsec.d/acerts'
Jan 22 17:17:40 00[CFG] loading crls from '/etc/ipsec.d/crls'
Jan 22 17:17:40 00[CFG] loading secrets from '/etc/ipsec.secrets'
Jan 22 17:17:40 00[CFG] loaded RSA private key from '/etc/ipsec.d/private/server-key.pem'
Jan 22 17:17:40 00[CFG] loaded EAP secret for ejohanson
Jan 22 17:17:40 00[CFG] sql plugin: database URI not set
Jan 22 17:17:40 00[CFG] opening triplet file /etc/ipsec.d/triplets.dat failed: No such file or directory
Jan 22 17:17:40 00[CFG] eap-simaka-sql database URI missing
Jan 22 17:17:40 00[CFG] loaded 0 RADIUS server configurations
Jan 22 17:17:40 00[CFG] HA config misses local/remote address
Jan 22 17:17:40 00[CFG] no threshold configured for systime-fix, disabled
Jan 22 17:17:40 00[CFG] coupling file path unspecified
Jan 22 17:17:40 00[LIB] loaded plugins: charon test-vectors unbound ldap pkcs11 tpm aesni aes rc2 sha2 sha1 md4 md5 mgf1 rdrand random nonce x509 revocation constraints acert pubkey pkcs1 pkcs7 pkcs8 pkcs12 pgp dnskey sshkey dnscert ipseckey pem openssl gcrypt af-alg fips-prf gmp curve25519 agent chapoly xcbc cmac hmac ctr ccm gcm ntru bliss curl soup mysql sqlite attr kernel-netlink resolve socket-default connmark farp stroke updown eap-identity eap-sim eap-sim-pcsc eap-aka eap-aka-3gpp2 eap-simaka-pseudonym eap-simaka-reauth eap-md5 eap-gtc eap-mschapv2 eap-dynamic eap-radius eap-tls eap-ttls eap-peap eap-tnc xauth-generic xauth-eap xauth-pam xauth-noauth tnc-tnccs tnccs-20 tnccs-11 tnccs-dynamic dhcp whitelist lookip error-notify certexpire led radattr addrblock unity counters
Jan 22 17:17:40 00[LIB] dropped capabilities, running as uid 0, gid 0
Jan 22 17:17:40 00[JOB] spawning 16 worker threads
Jan 22 16:50:23 05[CFG] received stroke: add connection 'ikev2-vpn'
Jan 22 16:50:23 05[CFG] adding virtual IP address pool 10.10.11.0/16
Jan 22 16:50:23 05[CFG] loaded certificate "CN=devsrv.valmarc.com" from 'server-cert.pem'
Jan 22 16:50:23 05[CFG] added configuration 'ikev2-vpn'
Jan 22 16:50:32 07[KNL] interface ens7 activated
Jan 22 16:50:32 10[KNL] interface ens6 activated
Jan 22 16:50:32 13[KNL] interface ens5 activated
Jan 22 16:50:32 10[KNL] 10.4.1.2 appeared on ens7
Jan 22 16:50:32 07[KNL] 10.3.1.2 appeared on ens6
Jan 22 16:50:33 12[KNL] 10.2.1.2 appeared on ens5
Jan 22 16:50:33 06[KNL] fe80::4001:aff:fe04:102 appeared on ens7
Jan 22 16:50:33 16[KNL] fe80::4001:aff:fe02:102 appeared on ens5
Jan 22 16:50:34 08[KNL] fe80::4001:aff:fe03:102 appeared on ens6
Jan 22 16:53:42 01[NET] received packet: from 73.249.XXX.YYY[500] to 10.1.1.2[500] (1104 bytes)
Jan 22 16:53:42 01[ENC] parsed IKE_SA_INIT request 0 [ SA KE No N(FRAG_SUP) N(NATD_S_IP) N(NATD_D_IP) V V V V ]
Jan 22 16:53:42 01[IKE] received MS NT5 ISAKMPOAKLEY v9 vendor ID
Jan 22 16:53:42 01[IKE] received MS-Negotiation Discovery Capable vendor ID
Jan 22 16:53:42 01[IKE] received Vid-Initial-Contact vendor ID
Jan 22 16:53:42 01[ENC] received unknown vendor ID: 01:52:8b:bb:c0:06:96:12:18:49:ab:9a:1c:5b:2a:51:00:00:00:02
Jan 22 16:53:42 01[IKE] 73.249.XXX.YYY is initiating an IKE_SA
Jan 22 16:53:42 01[CFG] received proposals: IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:3DES_CBC/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:3DES_CBC/HMAC_SHA2_384_192/PRF_HMAC_SHA2_384/MODP_1024, IKE:AES_CBC_128/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:AES_CBC_128/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_CBC_128/HMAC_SHA2_384_192/PRF_HMAC_SHA2_384/MODP_1024, IKE:AES_CBC_192/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:AES_CBC_192/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_CBC_192/HMAC_SHA2_384_192/PRF_HMAC_SHA2_384/MODP_1024, IKE:AES_CBC_256/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_CBC_256/HMAC_SHA2_384_192/PRF_HMAC_SHA2_384/MODP_1024, IKE:AES_GCM_16_128/PRF_HMAC_SHA1/MODP_1024, IKE:AES_GCM_16_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_GCM_16_128/PRF_HMAC_SHA2_384/MODP_1024, IKE:AES_GCM_16_256/PRF_HMAC_SHA1/MODP_1024, IKE:AES_GCM_16_256/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_GCM_16_256/PRF_HMAC_SHA2_384/MODP_1024
Jan 22 16:53:42 01[CFG] configured proposals: IKE:AES_CBC_128/AES_CBC_192/AES_CBC_256/AES_CTR_128/AES_CTR_192/AES_CTR_256/CAMELLIA_CBC_128/CAMELLIA_CBC_192/CAMELLIA_CBC_256/CAMELLIA_CTR_128/CAMELLIA_CTR_192/CAMELLIA_CTR_256/3DES_CBC/HMAC_SHA2_256_128/HMAC_SHA2_384_192/HMAC_SHA2_512_256/AES_XCBC_96/AES_CMAC_96/HMAC_SHA1_96/PRF_AES128_XCBC/PRF_AES128_CMAC/PRF_HMAC_SHA2_256/PRF_HMAC_SHA2_384/PRF_HMAC_SHA2_512/PRF_HMAC_SHA1/ECP_256/ECP_384/ECP_521/ECP_256_BP/ECP_384_BP/ECP_512_BP/CURVE_25519/NTRU_128/NTRU_192/NTRU_256/MODP_3072/MODP_4096/MODP_6144/MODP_8192/MODP_2048, IKE:AES_CCM_16_128/AES_CCM_16_192/AES_CCM_16_256/AES_GCM_16_128/AES_GCM_16_192/AES_GCM_16_256/CHACHA20_POLY1305_256/CAMELLIA_CCM_16_128/CAMELLIA_CCM_16_192/CAMELLIA_CCM_16_256/AES_CCM_8_128/AES_CCM_8_192/AES_CCM_8_256/AES_CCM_12_128/AES_CCM_12_192/AES_CCM_12_256/AES_GCM_8_128/AES_GCM_8_192/AES_GCM_8_256/AES_GCM_12_128/AES_GCM_12_192/AES_GCM_12_256/CAMELLIA_CCM_8_128/CAMELLIA_CCM_8_192/CAMELLIA_CCM_8_256/CAMELLIA_CCM_12_128/CAMELLIA_CCM_12_192/CAMELLIA_CCM_12_256/PRF_AES128_XCBC/PRF_AES128_CMAC/PRF_HMAC_SHA2_256/PRF_HMAC_SHA2_384/PRF_HMAC_SHA2_512/PRF_HMAC_SHA1/ECP_256/ECP_384/ECP_521/ECP_256_BP/ECP_384_BP/ECP_512_BP/CURVE_25519/NTRU_128/NTRU_192/NTRU_256/MODP_3072/MODP_4096/MODP_6144/MODP_8192/MODP_2048
Jan 22 16:53:42 01[IKE] local host is behind NAT, sending keep alives
Jan 22 16:53:42 01[IKE] remote host is behind NAT
Jan 22 16:53:42 01[IKE] received proposals inacceptable
Jan 22 16:53:42 01[ENC] generating IKE_SA_INIT response 0 [ N(NO_PROP) ]
Jan 22 16:53:42 01[NET] sending packet: from 10.1.1.2[500] to 73.249.XXX.YYY[500] (36 bytes)
作为参考，这是我的 /etc/ipsec.conf 文件：
config setup
charondebug="ike 1, knl 1, cfg 0"
uniqueids=no
conn ikev2-vpn
auto=add
compress=no
type=tunnel
keyexchange=ikev2
fragmentation=yes
forceencaps=yes
dpdaction=clear
dpddelay=300s
rekey=no
left=%any
[email protected]
leftcert=server-cert.pem
leftsendcert=always
leftsubnet=0.0.0.0/0
right=%any
rightid=%any
rightauth=eap-mschapv2
rightsourceip=10.10.11.0/16
rightdns=8.8.8.8,8.8.4.4
rightsendcert=never
eap_identity=%identity
有人能建议如何解决这个问题吗？
答案1
问题是 IKE 提议不匹配：
Jan 22 16:53:42 01[CFG] received proposals: IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:3DES_CBC/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:3DES_CBC/HMAC_SHA2_384_192/PRF_HMAC_SHA2_384/MODP_1024, IKE:AES_CBC_128/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:AES_CBC_128/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_CBC_128/HMAC_SHA2_384_192/PRF_HMAC_SHA2_384/MODP_1024, IKE:AES_CBC_192/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:AES_CBC_192/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_CBC_192/HMAC_SHA2_384_192/PRF_HMAC_SHA2_384/MODP_1024, IKE:AES_CBC_256/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_CBC_256/HMAC_SHA2_384_192/PRF_HMAC_SHA2_384/MODP_1024, IKE:AES_GCM_16_128/PRF_HMAC_SHA1/MODP_1024, IKE:AES_GCM_16_128/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_GCM_16_128/PRF_HMAC_SHA2_384/MODP_1024, IKE:AES_GCM_16_256/PRF_HMAC_SHA1/MODP_1024, IKE:AES_GCM_16_256/PRF_HMAC_SHA2_256/MODP_1024, IKE:AES_GCM_16_256/PRF_HMAC_SHA2_384/MODP_1024
Jan 22 16:53:42 01[CFG] configured proposals: IKE:AES_CBC_128/AES_CBC_192/AES_CBC_256/AES_CTR_128/AES_CTR_192/AES_CTR_256/CAMELLIA_CBC_128/CAMELLIA_CBC_192/CAMELLIA_CBC_256/CAMELLIA_CTR_128/CAMELLIA_CTR_192/CAMELLIA_CTR_256/3DES_CBC/HMAC_SHA2_256_128/HMAC_SHA2_384_192/HMAC_SHA2_512_256/AES_XCBC_96/AES_CMAC_96/HMAC_SHA1_96/PRF_AES128_XCBC/PRF_AES128_CMAC/PRF_HMAC_SHA2_256/PRF_HMAC_SHA2_384/PRF_HMAC_SHA2_512/PRF_HMAC_SHA1/ECP_256/ECP_384/ECP_521/ECP_256_BP/ECP_384_BP/ECP_512_BP/CURVE_25519/NTRU_128/NTRU_192/NTRU_256/MODP_3072/MODP_4096/MODP_6144/MODP_8192/MODP_2048, IKE:AES_CCM_16_128/AES_CCM_16_192/AES_CCM_16_256/AES_GCM_16_128/AES_GCM_16_192/AES_GCM_16_256/CHACHA20_POLY1305_256/CAMELLIA_CCM_16_128/CAMELLIA_CCM_16_192/CAMELLIA_CCM_16_256/AES_CCM_8_128/AES_CCM_8_192/AES_CCM_8_256/AES_CCM_12_128/AES_CCM_12_192/AES_CCM_12_256/AES_GCM_8_128/AES_GCM_8_192/AES_GCM_8_256/AES_GCM_12_128/AES_GCM_12_192/AES_GCM_12_256/CAMELLIA_CCM_8_128/CAMELLIA_CCM_8_192/CAMELLIA_CCM_8_256/CAMELLIA_CCM_12_128/CAMELLIA_CCM_12_192/CAMELLIA_CCM_12_256/PRF_AES128_XCBC/PRF_AES128_CMAC/PRF_HMAC_SHA2_256/PRF_HMAC_SHA2_384/PRF_HMAC_SHA2_512/PRF_HMAC_SHA1/ECP_256/ECP_384/ECP_521/ECP_256_BP/ECP_384_BP/ECP_512_BP/CURVE_25519/NTRU_128/NTRU_192/NTRU_256/MODP_3072/MODP_4096/MODP_6144/MODP_8192/MODP_2048
Jan 22 16:53:42 01[IKE] local host is behind NAT, sending keep alives
Jan 22 16:53:42 01[IKE] remote host is behind NAT
Jan 22 16:53:42 01[IKE] received proposals inacceptable
Jan 22 16:53:42 01[ENC] generating IKE_SA_INIT response 0 [ N(NO_PROP) ]
这是因为 Windows 客户端默认提出的唯一 Diffie-Hellman 组是弱 MODP_1024，而 strongSwan 多年前就将其从默认提案中删除了。
您可以修改客户端，使其使用更强的 DH 组（首选），或修改服务器的配置，使其接受客户端提出的弱组。请参阅我之前的回答了解详情。