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Lasse Michael Mølgaard
Asked: 2021-06-14 13:20:36 +0800 CST

iPhone 用户不连接 StrongSwan VPN，而 Android 和 Windows 10 用户可以？

  • 772

我有一个 StrongSwan VPN，由于某种我不知道的原因，它无法将 iOS 用户连接到我的 VPN 服务器。

一些快速说明：

  • 我的 StrongSwan 服务器是连接到我的网络的 VPN 客户端的前端。我用于WireGuard我的后端站点到站点路由。

  • 所有 StrongSwan VPN 用户都经过FreeRadius服务器验证。

  • StrongSwan 客户端在子网上被分配一个 IP 192.168.201.0/24，而 WireGuard 主干网络在192.168.200.0/24子网上运行。

  • 所有客户端也都获得了一个公共 IPv6 地址，该地址属于分配给我的 /48 子网。

我在 Ubuntu 20.04 上运行 StrongSwan，我的配置文件位于该/etc/swanctl/config/文件夹中，由于文件名以.conf.

内容如下：

# Default VPN server settings for all connections
conn-defaults {
    local_addrs = PUBLIC_IPV4, PUBLIC_IPV6

    local {
      auth = pubkey
      certs = vpn-ecdsa.cer
      id = vpn.example.com
    }

    version = 2
    send_certreq = no
    send_cert = always
    unique = never
    fragmentation = yes
    encap = yes
    dpd_delay = 60s

    rekey_time = 0s
}

# Default login method
eap-defaults {
  remote {
   auth = eap-radius
   id = %any
   eap_id = %any
  }
}

connections
{
  # Generic Android configuration that is extended further down.
  #
  # Works with StrongSwan VPN client for Android
  conn-unix : conn-defaults, eap-defaults {
    children {
      net {
        local_ts = 0.0.0.0/0, ::/0
      }

      net-unix : child-defaults {
      }

      esp_proposals = aes128gcm128-x25519
    }

    proposals = aes128-sha256-x25519
  }

  # All Windows klients matches this rule as username validation 
  # is done by 'eap_start = yes' in strongswan.conf. 
  #
  # Works with Windows 10 built-in VPN client.
  conn-windows : conn-defaults, eap-defaults {
    children {
      net {
        local_ts = 0.0.0.0/0, ::/0
      }

      esp_proposals = aes256-sha256-prfsha256-modp1024
    }

    proposals = aes256-sha256-prfsha256-modp1024
    pools = IkeVPN-site-ipv4, IkeVPN-site-ipv6

  }

  # A very similar configuration to Windows clients 
  # configuration, except iOS uses 2048 bit keys, 
  # while Windows uses 1024 bit keys.
  #
  # Does NOT work in its current state.
  conn-ios : conn-defaults, eap-defaults {
    children {
      net {
        local_ts = 0.0.0.0/0, ::/0
      }

      esp_proposals = aes256-sha2_256
      pools = IkeVPN-site-ipv4, IkeVPN-site-ipv6

    }

    proposals = aes256-sha256-prfsha256-modp2048
  }

  # Android users is matched against this connection as they are 
  # running the app StrongSwan VPN client. Username is passed in the
  # 'id' field to StrongSwan VPN server.
  conn-unix-site : connections.conn-unix {
    remote {
      id = *@site.example.com
    }
    pools = IkeVPN-site-ipv4, IkeVPN-site-ipv6
  }
}

pools
{
   IkeVPN-site-ipv4 {
      addrs = 192.168.201.0/24
      dns = 192.168.200.1
   }

   IkeVPN-site-ipv6 {
      addrs = 2001:db8:cafe::/97
      dns = 2001:db8::1
   }
}

我的配置是使用以下网页给出的结构创建的：

https://wiki.strongswan.org/projects/strongswan/wiki/Strongswanconf#Referencing-other-Sections

我使用它的原因是避免在我的所有连接配置文件中重复相同的配置设置。

如果您不熟悉此设置，conn-ios则应将以下配置视为等效：

conn-ios {
   # Obtained from conn-default
   local_addrs = PUBLIC_IPV4, PUBLIC_IPV6

   local {
      auth = pubkey
      certs = vpn-ecdsa.cer
      id = vpn.example.com
   }

   version = 2
   send_certreq = no
   send_cert = always
   unique = never
   fragmentation = yes
   encap = yes
   dpd_delay = 60s

   rekey_time = 0s

   # Obtained from eap-defaults
   remote {
      auth = eap-radius
      id = %any
      eap_id = %any
   }

   # Obtained from original conn-ios profile above.
   children {
      net {
         local_ts = 0.0.0.0/0, ::/0
      }

      esp_proposals = aes256-sha2_256
      pools = IkeVPN-site-ipv4, IkeVPN-site-ipv6
   }

   proposals = aes256-sha256-prfsha256-modp2048
}

本conn-default节中列出的服务器证书是使用 Acme.sh 从 Let's Encrypt 获得的 ECDSA 证书。

proposalsiOS 配置中的加密值esp_proposals取自https://wiki.strongswan.org/projects/strongswan/wiki/AppleClients中的提示。

在测试 Android 或 Windows 用户的所有组合时，连接没有任何问题，但是当有人尝试使用 iPhone 登录时，连接就会停止。

iPhone尝试连接时的日志输出如下：

10[IKE] CLIENT_IPV4 is initiating an IKE_SA
10[CFG] received proposals: IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_2048, IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/ECP_256, IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1536, IKE:AES_CBC_128/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024
10[CFG] configured proposals: IKE:AES_CBC_128/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/CURVE_25519
10[IKE] no matching proposal found, trying alternative config
10[CFG] received proposals: IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_2048, IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/ECP_256, IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1536, IKE:AES_CBC_128/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024
10[CFG] configured proposals: IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_1024
10[IKE] no matching proposal found, trying alternative config
10[CFG] selected proposal: IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_2048
10[IKE] remote host is behind NAT
10[ENC] generating IKE_SA_INIT response 0 [ SA KE No N(NATD_S_IP) N(NATD_D_IP) N(FRAG_SUP) N(CHDLESS_SUP) N(MULT_AUTH) ]
10[NET] sending packet: from PUBLIC_IPV4[500] to CLIENT_IPV4[6452] (456 bytes)
06[NET] received packet: from CLIENT_IPV4[13549] to PUBLIC_IPV4[4500] (512 bytes)
06[ENC] unknown attribute type INTERNAL_DNS_DOMAIN
06[ENC] parsed IKE_AUTH request 1 [ IDi N(INIT_CONTACT) IDr CPRQ(ADDR MASK DHCP DNS ADDR6 DHCP6 DNS6 DOMAIN) N(ESP_TFC_PAD_N) N(NON_FIRST_FRAG) SA TSi TSr N(MOBIKE_SUP) ]
06[CFG] looking for peer configs matching PUBLIC_IPV4[vpn.example.com]...CLIENT_IPV4[PRIVATE_CLASS_A_ADDRESS]
06[CFG] selected peer config 'conn-ios'
06[IKE] initiating EAP_IDENTITY method (id 0x00)
06[IKE] received ESP_TFC_PADDING_NOT_SUPPORTED, not using ESPv3 TFC padding
06[IKE] peer supports MOBIKE
06[IKE] authentication of 'vpn.example.com' (myself) with ECDSA-256 signature successful
06[IKE] sending end entity cert "CN=vpn.example.com"
06[IKE] sending issuer cert "C=US, O=Let's Encrypt, CN=R3"
06[ENC] generating IKE_AUTH response 1 [ IDr CERT CERT AUTH EAP/REQ/ID ]
06[ENC] splitting IKE message (2816 bytes) into 3 fragments
06[ENC] generating IKE_AUTH response 1 [ EF(1/3) ]
06[ENC] generating IKE_AUTH response 1 [ EF(2/3) ]
06[ENC] generating IKE_AUTH response 1 [ EF(3/3) ]
06[NET] sending packet: from PUBLIC_IPV4[4500] to CLIENT_IPV4[13549] (1236 bytes)
06[NET] sending packet: from PUBLIC_IPV4[4500] to CLIENT_IPV4[13549] (1236 bytes)
06[NET] sending packet: from PUBLIC_IPV4[4500] to CLIENT_IPV4[13549] (500 bytes)
11[JOB] deleting half open IKE_SA with CLIENT_IPV4 after timeout

iPhone 用户使用以下设置使用内置 VPN 客户端进行连接：

  • 类型 IKEv2

  • 描述：VPN服务器

  • 服务器：vpn.example.com

  • 远程 ID：vpn.example.com

  • 本地标识：空白

  • 用户名和密码验证。

  • 用户名：[email protected]

  • 密码：ItIsASecret

有谁知道为什么 iOS 用户在加载conn-ios配置文件时连接会停止？

更新 我们起飞了！:-)

根据@ecdsa 的建议，我已将证书切换为 2048 位 RSA 证书。

我的 Radius 服务器被调用。用户身份验证成功，客户端获得分配 IP 地址。我很开心。:-)

我conn-ios现在的配置是：

  conn-ios : conn-defaults, eap-defaults {

    # Overriding defaults from 'conn-default'
    local {
      auth = pubkey
      certs = vpn-rsa.cer
      id = vpn.example.com
    }

    children {
      net {
        local_ts = 0.0.0.0/0, ::/0
      }

      esp_proposals = aes256-sha256
    }

    pools = IkeVPN-site-ipv4, IkeVPN-site-ipv6
    proposals = aes256-sha256-prfsha256-modp2048
  }

其他一切都与我的初始配置一样。

iphone strongswan apple-ios ikev2

1 个回答

  1. Best Answer

    正如我们在日志中看到的，客户端不支持RFC 7427（否则，哈希算法通知将在 期间交换IKE_SA_INIT），它定义了灵活的基于签名的身份验证。

    虽然 IKEv2 也支持没有该扩展的 ECDSA，但RFC 4754仅添加了对它的有限支持（只能使用三个 NIST 曲线，并且每个曲线都分配了特定的哈希算法）。因此，如果在配置文件中明确配置，Apple 客户端可能只接受/使用 ECDSA （有一个选项CertificateType可以设置为 eg ECDSA256）。

    如果使用配置文件不是一个选项，唯一的选择是使用RSA 服务器证书，至少在 Apple 在其 IKEv2 客户端中实现对 RFC 7427 的支持之前。

    • 0

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