IKE traffic leaving your on-premises network is sourced from your configured customer gateway IP address on UDP port 500. To test this setting, disable NAT traversal on your customer gateway device. UDP packets on port 500 (and port 4500, if you're using NAT traversal) are allowed to pass between your network and AWS VPN endpoints.
查看IKE SA是否存在 2011-2-23 · 检查ike的安全策略（到自身的安全策略和从自身发送的安全策略）是否放行。 执行命令 display firewall session table verbose destination-port global 500 确认有没有IKE的会话。 Solved: VPN ipsec and port 500 - Cisco Community There is NAT/PAT in between R3 and ASA. as you use private IP address(192.168.98.6) to setup the ipsec session. IKE will detect NAT/PAT exist by NAT-D payload. IKE will use UDP 4500 to negotiate ISAKMP rather than UDP 500. Afterwards, ESP traffic is also encapsulated in UDP 4500, in this way it can traverse NAT/PAT safely. IPsec VPN_百度百科
However, if NAT is happening anywhere in between the client and the server, you should be using IPSec NAT Traversal (NAT-T), and you don't have to permit IP proto 50 (and/or 51), you just have to permit UDP/500 (IKE) and UDP/4500 (NAT-T) to the VPN server.
To distinguish them from IKE packets the latter are modified so they contain four zero bytes right after the UDP header where the SPI is located in ESP packets (known as "non-ESP marker"). This means that the UDP socket/port (4500 by default) has to handle traffic differently than the default IKE socket/port. 500/udp - Pentesting IPsec/IKE VPN - HackTricks 2020-6-22 · IKE is a type of ISAKMP (Internet Security Association Key Management Protocol) implementation, which is a framework for authentication and key exchange. Also, using IPSec try to make a MitM attack and block all traffic to port 500, if the IPSec tunnel cannot be established maybe the traffic will be sent in clear.
H3C MSR(V7) IPSec VPN野蛮模板方式IKE超时导 … 2018-3-31 · port link-mode route ip address 2.2.2.2 255.255.255.252 nat outbound 3001 ipsec apply policy h3cnc # 检查分支基本配置无异常，在分支MSR设备上开启debug ike all，使用感兴趣流触发IPSec VPN建立，观察报文交互情况，其中： QCombox下拉框宽度调整 - ike_li - 博客园 2020-3-5 · ike_li 耐住寂寞 博客园 首页 新随笔 联系 订阅 管理 随笔 - 427 文章 - 178 评论 - 38 QCombox下拉框宽度调整 #include