GRE Transmit Loop Detected

RouterOS Forwarding Protocols
1

This is our first Site to Site VPN. We have selected GRE over IPSEC. Below is the script for our configuration. I have been unable to establish the GRE tunnel due to the error “GRE Transmit Loop Detected”. The IPSEC is established and operating.

I appreciate any help.

SiteA - CCR1036 RouterOS 6.40.5
SiteB - CCR1036 RouterOS 6.41.4

SITE A
/ip ipsec peer
add address=XX.XX.127.82/32 comment=SiteBDataCenter enc-algorithm=aes-128 nat-traversal=no secret=SECRET
/ip ipsec policy
add comment=SiteBDataCenter dst-address=10.0.0.2/32 sa-dst-address=XX.XX.127.82 sa-src-address=XX.XX.144.162 src-address=10.0.0.1/32 tunnel=yes
/interface gre
add comment=SiteBDataCenter !keepalive local-address=10.0.0.1 name=“SiteBDataCenter GRE” remote-address=10.0.0.2
/ip address
add address=10.0.0.1/30 interface=“SiteBDataCenter GRE” network=10.0.0.0
/ip route
add comment=“SiteBDataCenter LAN” distance=1 dst-address=10.1.2.0/30 gateway=10.0.0.2

SITE B
/ip ipsec peer
add address=XX.XX.144.162/32 comment=SiteADataCenter enc-algorithm=aes-128 nat-traversal=no secret=SECRET
/ip ipsec policy
add comment=SiteADataCenter dst-address=10.0.0.1/32 sa-dst-address=XX.XX.144.162 sa-src-address=XX.XX.127.82 src-address=10.0.0.2/32 tunnel=yes
/interface gre
add comment=SiteADataCenter !keepalive local-address=10.0.0.2 name=“SiteADataCenter GRE” remote-address=10.0.0.1
/ip address
add address=10.0.0.2/30 interface=“SiteADataCenter GRE” network=10.0.0.0
/ip route
add comment=“SiteADataCenter LAN” distance=1 dst-address=10.1.1.0/30 gateway=10.0.0.1

2

Let me fix it for you:

/ip ipsec policy
add comment=SiteBDataCenter dst-address=XX.XX.127.82/32 sa-dst-address=XX.XX.127.82 sa-src-address=XX.XX.144.162 src-address=XX.XX.144.162/32 tunnel=no protocol=gre
/interface gre
add comment=SiteBDataCenter !keepalive local-address=XX.XX.144.162 name=“SiteBDataCenter GRE” remote-address=XX.XX.127.82

And same for the other side.

3

Sob,

Thank you. That appears to have resolved my issue.

dmc