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New Contributor

VPN Alert - Received ESP packet with unknown SPI

Hello All.

Do someone know if I can block this action?

Message meets Alert condition date=2018-09-12 time=15:12:16 devname=FGTxx devid=FGTxx logid=0101037131 type=event subtype=vpn level=error vd=root logdesc="IPsec ESP" msg="IPsec ESP" action=error remip= locip= remport=36979 locport=500 outintf="wan1" cookies="N/A" user="N/A" group="N/A" xauthuser="N/A" xauthgroup="N/A" assignip=N/A vpntunnel="N/A" status=esp_error error_num="Received ESP packet with unknown SPI." spi="47455420" seq="2f204854".


I created new policy for test, but not sure that it will help.

config firewall policy edit 39 set name "Block from wan" set uuid c23ca428-c089-51e8-7cff-b2ab3289eec7 set srcintf "wan1" "wan2" set dstintf "internal" set srcaddr "abusers_OVH-FR" "Country Restriction" set dstaddr "all" set schedule "always" set service "ALL" set logtraffic all next end


I do have local-in-policy, that should block any VPN connections:

config firewall local-in-policy edit 1 set intf "wan1" set srcaddr "DC-GATEWAY-VPN" set dstaddr "office1_vpn" set action accept set service "IKE" "ESP" set schedule "always" next edit 2 set intf "wan2" set srcaddr "DC-GATEWAY-VPN" set dstaddr "office2_vpn" set action accept set service "IKE" "ESP" set schedule "always" next edit 3 set intf "any" set srcaddr "all" set dstaddr "all" set service "IKE" "ESP" set schedule "always" next end


Thanks in advance!


Valued Contributor II

A number of us have been seeing this.  See for the discussion.


So far the answer has been "by design" due to the way the FortiGate is handling UDP 4500 (translated to UDP 500) *before* local-in-policy, but I'm hoping we can get them to reconsider that.

New Contributor

Thank you for the answer!


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