Hi Christopher, Based on the fact that you get 2 pings through before it fails, I suspect that the route to the remote end of the EoIP tunnel changes, most likely to be going over the tunnel itself. Since the tunnel can't be established via itself, it then drops. You may need to add in a static route for the single IP address that is the remote end of the tunnel to ensure it always takes the "underlay" path. Regards, Philip Loenneker| Senior Network Engineer TasmaNet | Vastnet | Netmode -----Original Message----- From: Public <public-bounces@talk.mikrotik.com.au> On Behalf Of Christopher Hawker Sent: Monday, 6 September 2021 9:01 AM To: public@talk.mikrotik.com.au Subject: [MT-AU Public] EoIP Tunnel that doesn't want to tunnel Hi Everyone, I for some reason, have two MT devices (A-side is a CCR1009-8G-1S-1S+ and the Z-side is a CHR) and they don't seem to want to tunnel together. The tunnel comes up, two ICMP packets get through, and the link goes down. There is no firewalling in place (or has been disabled altogether for testing purposes) however the issue still manifests. The only thing is on the A side the public IP address is received by DHCP, however a reservation has been set by the carrier so the address will not change. *** A Side *** /interface eoip add allow-fast-path=no disabled=yes ipsec-secret="fakepass" local-address=192.0.2.10 mac-address=12:34:56:78:90:12 name=tun1 remote-address=203.0.113.10 tunnel-id=1 /ip address add address=172.21.254.2/30 interface=tun1 network=172.21.254.0 *** Z Side *** /interface eoip add allow-fast-path=no disabled=yes ipsec-secret="fakepass" local-address=203.0.113.10 mac-address=21:09:87:65:43:21 name=tun1 remote-address=192.0.2.10 tunnel-id=1 /ip address add address=203.0.113.10/29 interface=ether1 network=27.32.52.8 add address=172.21.254.1/30 interface=tun1 network=172.21.254.0 If anyone would be able to point out any issues or have any ideas, it'd be much appreciated! Thanks, Christopher Hawker _______________________________________________ Public mailing list Public@talk.mikrotik.com.au https://aus01.safelinks.protection.outlook.com/?url=http%3A%2F%2Ftalk.mikrot...