Hello
can you confirm the below, how you have done the icap integration?
1. do you have checkpoint dedicated appliance.
2.are you doing icap integration between f5 and sandblast or between any firewall to sandblast.
3.which is the perimeter firewall.
4.how is the flow of your inbound and outbound traffic ( it is compulsory to understand your design)
Use case 1:
-----------
if you are doing icap integration between checkpoint firewall and sandblast then enable threat extraction and https inspection on firewall and only enable threat emulation and Anti virus on sandblast appliance for both MTA traffic as well as icap traffic.
Note: Once you will enable the icap services on both ways then span port will not come into picture. And icap service will not follow the complete web traffic it will only look into attachments.
use case 2:
-----------
if yo are doing icap integraion between 3rd party firewall to checkpoint sandblast, how you are sending the traffic to sandblast.
once you will revert back then may be we can assist you in the proper direction.