We are doing migration of API from CA Layer7 to Apigee. There are lots of API which running on mutual TLS for inbound request . As per migration plan we are going with approach of first brining apigee layer in front of CA Layer7 and route all traffic from apigee to Layer7 .
Since apigee breaks TLS in proxy endpoint before routing the request to target there is additional effort required to bind the certificate to target endpoint . Is this possible to make TLS pass through from apigee to Backend system (CA Layer7 here)
No, if I understand your question correctly: it is not possible to configure the Apigee proxy to act as a layer-4 proxy, which is necessary to “passthrough” the encrypted packets to the backend system, without terminating the inbound TLS connection and initiating a new TLS connection southbound.
Apigee acts as a layer-7 (Not Layer7 ™) proxy. It terminates inbound TLS connections, and initiates new TLS connections outbound.
To follow the process you are imagining, I think you will need to
EITHER configure the Layer7 gateway to accept an additional new set of TLS keys, and provision those new keys in Apigee for southbound connections
OR, configure the Apigee to use the existing TLS keys and certs for its southbound connections.