我们在 Linux 上运行 racoon 来连接 Checkpoint 防火墙。连接正常，但是我们发现每 24 小时就会出现一次流量中断，这与第 1 阶段的重新协商相对应。
我们的设置如下：
本地端
来自 ipsec-tools 0.8.0 的 racoon 从 Amazon Linux 上的 RPM 安装。
本地IP：10.130.0.253
本地子网：10.130.0.252/30
它运行在 AWS VPC 内，即在私有子网上。因此我们启用了 NAT 遍历。我们将 VPN 绑定到子接口，并使用 iptables 将 VPN 连接转换为主地址，并将发往远程 LAN 的 NAT 流量转换为子接口。这允许主机充当其他主机的 VPN 网关，效果很好。Iptables 规则：
Chain POSTROUTING (policy ACCEPT)
target prot opt source destination
SNAT all -- 10.130.0.253 2.2.2.2 to:10.100.200.112
SNAT all -- 0.0.0.0/0 10.128.80.0/24 to:10.130.0.253
远端：
VPN 网关 IP：2.2.2.2（匿名）
远程子网：10.128.80.0/24
我们的本地配置如下：
/etc/racoon/racoon.conf：
# Racoon IKE daemon configuration file.
# See 'man racoon.conf' for a description of the format and entries.
log debug2;
path include "/etc/racoon";
path pre_shared_key "/etc/racoon/psk.txt";
path certificate "/etc/racoon/certs";
path script "/etc/racoon/scripts";
# Listen on sub-interface - initial connection to establish tunnel is translated to primary IP by iptables
listen {
isakmp 10.130.0.253 [500];
isakmp_natt 10.130.0.253 [4500];
}
timer {
natt_keepalive 1 minute ;
}
# CP VPN-1
remote 2.2.2.2
{
exchange_mode main;
lifetime time 24 hour;
nat_traversal on;
dpd_delay 20;
proposal {
encryption_algorithm 3des;
hash_algorithm sha1;
authentication_method pre_shared_key;
dh_group 2;
}
}
# net-to-net
sainfo address 10.130.0.252/30 any address 10.128.80.0/24 any
{
pfs_group 2;
lifetime time 1 hour;
encryption_algorithm 3des;
authentication_algorithm hmac_sha1 ;
compression_algorithm deflate ;
}
# gateway to gateway
sainfo address 10.130.0.253/32 any address 2.2.2.2/32 any
{
lifetime time 1 hour;
encryption_algorithm 3des;
authentication_algorithm hmac_sha1 ;
compression_algorithm deflate ;
}
设置密钥的命令
#!/sbin/setkey -f
# First of all flush the SPD database
flush;
spdflush;
# Gateway to Gateway
spdadd 10.130.0.253 2.2.2.2 any -P out ipsec esp/tunnel/10.130.0.253-2.2.2.2/unique;
spdadd 2.2.2.2 10.130.0.253 any -P in ipsec esp/tunnel/2.2.2.2-10.130.0.253/unique;
# Linux-racoon -> CP VPN-1
spdadd 10.130.0.252/30 10.128.80.0/24 any -P out ipsec esp/tunnel/10.130.0.253-2.2.2.2/unique;
# CP VPN-1 > Linux-racoon
spdadd 10.128.80.0/24 10.130.0.252/30 any -P in ipsec esp/tunnel/2.2.2.2-10.130.0.253/unique;
最近，我们在监控 VPN 时收到一些警报，因此我设置了一个更详细的监控脚本，该脚本每分钟连接到远程服务器一次。似乎我们每 24 小时就会出现一次严重的停机时间。我的脚本显示连接何时断开以及何时恢复：
Fri Jan 18 20:24:33 UTC 2013 Connection went down
Fri Jan 18 20:48:36 UTC 2013 Connection came up
Sat Jan 19 20:48:36 UTC 2013 Connection went down
Sat Jan 19 21:00:40 UTC 2013 Connection came up
Sun Jan 20 21:00:38 UTC 2013 Connection went down
Sun Jan 20 21:12:43 UTC 2013 Connection came up
如您所见，该连接在上次建立后 24 小时恰好断开。
这些中断似乎与 VPN 日志中的第 1 阶段重新协商相对应，这是有道理的，因为第 1 阶段的生命周期为 24 小时：
星期五：
Jan 18 20:24:32 ip-10-100-200-112 racoon: INFO: ISAKMP-SA expired 10.130.0.253[500]-2.2.2.2[500] spi:13b2510d0bc467f9:ff649237b81a65b7
Jan 18 20:24:32 ip-10-100-200-112 racoon: INFO: ISAKMP-SA deleted 10.130.0.253[500]-2.2.2.2[500] spi:13b2510d0bc467f9:ff649237b81a65b7
Jan 18 20:36:34 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 2.2.2.2[500]->10.130.0.253[500] spi=213727991(0xcbd3af7)
Jan 18 20:36:34 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=3400029604(0xcaa855a4)
Jan 18 20:48:34 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 2.2.2.2[500]->10.130.0.253[500] spi=213727991(0xcbd3af7)
Jan 18 20:48:34 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=3400029604(0xcaa855a4)
Jan 18 20:48:34 ip-10-100-200-112 racoon: INFO: IPsec-SA request for 2.2.2.2 queued due to no phase1 found.
Jan 18 20:48:34 ip-10-100-200-112 racoon: INFO: initiate new phase 1 negotiation: 10.130.0.253[500]<=>2.2.2.2[500]
Jan 18 20:48:34 ip-10-100-200-112 racoon: INFO: begin Identity Protection mode.
Jan 18 20:48:34 ip-10-100-200-112 racoon: INFO: ISAKMP-SA established 10.130.0.253[500]-2.2.2.2[500] spi:c4978718cd291fde:01245a461d26cc34
Jan 18 20:48:35 ip-10-100-200-112 racoon: INFO: initiate new phase 2 negotiation: 10.130.0.253[500]<=>2.2.2.2[500]
Jan 18 20:48:35 ip-10-100-200-112 racoon: INFO: IPsec-SA established: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=264213233(0xfbf92f1)
Jan 18 20:48:35 ip-10-100-200-112 racoon: INFO: IPsec-SA established: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=919162535(0x36c94ea7)
周六：
Jan 19 20:48:34 ip-10-100-200-112 racoon: INFO: ISAKMP-SA expired 10.130.0.253[500]-2.2.2.2[500] spi:c4978718cd291fde:01245a461d26cc34
Jan 19 20:48:34 ip-10-100-200-112 racoon: INFO: ISAKMP-SA deleted 10.130.0.253[500]-2.2.2.2[500] spi:c4978718cd291fde:01245a461d26cc34
Jan 19 20:48:36 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 2.2.2.2[500]->10.130.0.253[500] spi=229822093(0xdb2ce8d)
Jan 19 20:48:36 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=2536548534(0x9730a8b6)
Jan 19 21:00:36 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 2.2.2.2[500]->10.130.0.253[500] spi=229822093(0xdb2ce8d)
Jan 19 21:00:36 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=2536548534(0x9730a8b6)
Jan 19 21:00:37 ip-10-100-200-112 racoon: INFO: IPsec-SA request for 2.2.2.2 queued due to no phase1 found.
Jan 19 21:00:37 ip-10-100-200-112 racoon: INFO: initiate new phase 1 negotiation: 10.130.0.253[500]<=>2.2.2.2[500]
Jan 19 21:00:37 ip-10-100-200-112 racoon: INFO: begin Identity Protection mode.
Jan 19 21:00:38 ip-10-100-200-112 racoon: INFO: ISAKMP-SA established 10.130.0.253[500]-2.2.2.2[500] spi:8b7e98a2cc9d55cb:0b4e8a4cbca2ada9
Jan 19 21:00:38 ip-10-100-200-112 racoon: INFO: initiate new phase 2 negotiation: 10.130.0.253[500]<=>2.2.2.2[500]
Jan 19 21:00:39 ip-10-100-200-112 racoon: INFO: IPsec-SA established: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=111999639(0x6acfa97)
Jan 19 21:00:39 ip-10-100-200-112 racoon: INFO: IPsec-SA established: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=577442054(0x226b1106)
星期日：
Jan 20 21:00:38 ip-10-100-200-112 racoon: INFO: ISAKMP-SA expired 10.130.0.253[500]-2.2.2.2[500] spi:8b7e98a2cc9d55cb:0b4e8a4cbca2ada9
Jan 20 21:00:38 ip-10-100-200-112 racoon: INFO: ISAKMP-SA deleted 10.130.0.253[500]-2.2.2.2[500] spi:8b7e98a2cc9d55cb:0b4e8a4cbca2ada9
Jan 20 21:00:39 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 2.2.2.2[500]->10.130.0.253[500] spi=131435403(0x7d58b8b)
Jan 20 21:00:39 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=272995718(0x10459586)
Jan 20 21:12:39 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 2.2.2.2[500]->10.130.0.253[500] spi=131435403(0x7d58b8b)
Jan 20 21:12:39 ip-10-100-200-112 racoon: INFO: IPsec-SA expired: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=272995718(0x10459586)
Jan 20 21:12:40 ip-10-100-200-112 racoon: INFO: IPsec-SA request for 2.2.2.2 queued due to no phase1 found.
Jan 20 21:12:40 ip-10-100-200-112 racoon: INFO: initiate new phase 1 negotiation: 10.130.0.253[500]<=>2.2.2.2[500]
Jan 20 21:12:40 ip-10-100-200-112 racoon: INFO: begin Identity Protection mode.
Jan 20 21:12:40 ip-10-100-200-112 racoon: INFO: ISAKMP-SA established 10.130.0.253[500]-2.2.2.2[500] spi:e6d2b9ccb25f4992:31807020144b9a1e
Jan 20 21:12:41 ip-10-100-200-112 racoon: INFO: initiate new phase 2 negotiation: 10.130.0.253[500]<=>2.2.2.2[500]
Jan 20 21:12:41 ip-10-100-200-112 racoon: INFO: IPsec-SA established: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=179370287(0xab0f92f)
Jan 20 21:12:41 ip-10-100-200-112 racoon: INFO: IPsec-SA established: ESP/Tunnel 10.130.0.253[500]->2.2.2.2[500] spi=1696204357(0x651a0645)
因此，第一阶段重新协商似乎至少需要 12 分钟。有人知道这可能是为什么吗？我们可以做些什么来解决这个问题，以便我们能够通过 VPN 实现不间断的流量？
答案1
如果您启用死对等检测，Racoon 应该会检测第 1 阶段的到期情况，并自动重新协商，假设我已经正确诊断了问题。
默认情况下，dpd 是关闭的；
dpd_delay 0；是默认值。
在 dpd 检查之间设置一个合理的数字（以秒为单位）将启用它；
dpd_延迟 30；
现在愤怒地在做同样事情的 ipsec vpn 上尝试这个。
答案2
抱歉，我得自己回答这个问题——我从 ipsec-tools 转到 Openswan，现在 VPN 已经完全稳定了。看来 ipsec-tools 是一个死项目，而 Openswan 仍在维护，现在是 RHEL 中的默认 VPN 解决方案。