IPsec VPN, IKE/SA is not established + ping between LANs does not work

[Lovro Zafosnik]

Hello everyone,

I’m working on my thesis and building a site-to-site IPsec VPN tunnel in Cisco Packet Tracer between two branch offices. Routing works without IPsec, but once the tunnel is configured, LAN-to-LAN communication does not work and IKE/IPsec SAs do not fully establish.

This is my topology :

Company A Network

Device Role Interface IP Address Subnet Mask Default Gateway

Router A	LAN Gateway	G0/0	192.168.1.1	255.255.255.0	—
Router A	WAN to Internet Router	S0/0/0	10.1.1.2	255.255.255.252	—
PC-A1	Client	NIC	192.168.1.10	255.255.255.0	192.168.1.1
Server-A (optional)	DNS / Intranet	NIC	192.168.1.20	255.255.255.0	192.168.1.1

---

Company B Network

Device Role Interface IP Address Subnet Mask Default Gateway

Router B	LAN Gateway	G0/0	192.168.2.1	255.255.255.0	—
Router B	WAN to Internet Router	S0/0/0	10.1.2.2	255.255.255.252	—
PC-B1	Client	NIC	192.168.2.10	255.255.255.0	192.168.2.1
Server-B (optional)	DNS / Intranet	NIC	192.168.2.20	255.255.255.0	192.168.2.1

---

Internet / Intermediate Router

Device Role Interface IP Address Subnet Mask

Internet Router	Transit Router	G0/0	10.1.1.1	255.255.255.252
Internet Router	Transit Router	G0/1	10.1.2.1	255.255.255.252

---

Static Routes Configuration (Required for Full Connectivity)

Router A:

ip route 192.168.2.0 255.255.255.0 10.1.1.1

Router B:

ip route 192.168.1.0 255.255.255.0 10.1.2.1

Internet Router:

ip route 192.168.1.0 255.255.255.0 10.1.1.2 ip route 192.168.2.0 255.255.255.0 10.1.2.

 If you know how I can fix this, I would be very grateful.

[balaji.bandi · Accepted solution]

If this packet tracer

have look this video and troubleshooting :

https://www.youtube.com/watch?v=CsAROSbZF-Y