Google VPN, site-to-site IPSec

Hello guys!

I am absolutely new to networking and because our network guy left, everything was transfered to me. I need to set up VPN between Google Cloud and our network. As far as i know, it should be IPSec site-to-site, but I don’t know how to achieve that properly. I have tried setting it up in Google Cloud by last advices I got from our former network guy, but it ends on first handshake. Google VPN IP is 35.205.116.142, our public IP is 109.235.177.120. This is the log:
D sending packet: from 35.205.116.142[4500] to 109.235.177.120[4500] (108 bytes)
D received packet: from 109.235.177.120[4500] to 35.205.116.142[4500] (76 bytes)
D parsed ID_PROT response 0 [ ID HASH ]
D IDir ‘192.168.41.19’ does not match to ‘109.235.177.120’
I deleting IKE_SA vpn_109.235.177.120[31] between 35.205.116.142[35.205.116.142]…109.235.177.120[%any]
D sending DELETE for IKE_SA vpn_109.235.177.120[31]
D generating INFORMATIONAL_V1 request 460923894 [ HASH D ]
D sending packet: from 35.205.116.142[4500] to 109.235.177.120[4500] (92 bytes)
D creating acquire job for policy with reqid {1}
I initiating Main Mode IKE_SA vpn_109.235.177.120[32] to 109.235.177.120
D generating ID_PROT request 0 [ SA V V V V ]
D sending packet: from 35.205.116.142[500] to 109.235.177.120[500] (156 bytes)
D received packet: from 109.235.177.120[500] to 35.205.116.142[500] (136 bytes)
D parsed ID_PROT response 0 [ SA V V V ]
D received NAT-T (RFC 3947) vendor ID
D received XAuth vendor ID
D received DPD vendor ID
D generating ID_PROT request 0 [ KE No NAT-D NAT-D ]
D sending packet: from 35.205.116.142[500] to 109.235.177.120[500] (244 bytes)
D received packet: from 109.235.177.120[500] to 35.205.116.142[500] (236 bytes)
D parsed ID_PROT response 0 [ KE No NAT-D NAT-D ]
D remote host is behind NAT
D generating ID_PROT request 0 [ ID HASH N(INITIAL_CONTACT) ]
As far as I understand, there is something bad with translating IPs on our side. Any help please?

Hi Lubomír,

do I read it right that you run a virtual Mikrotik in the google cloud and the log is from there, and that the Mikrotik in your premises doesn’t have the public address on one of its own interfaces?

If so, it should be sufficient to either choose ikev2 as exhange mode (at both ends) or to tick “nat traversal support” in peer configuration (at both ends). In either case, “tunnel mode” must be ticked.

Otherwise tell me more about your setup and provide output of “/export hide-sensitive” (in WinBox or WebFig, use “terminal” to get to command line).