ASA same-security-traffic permit inter-interface vs ACL
I have ASA 5525 with subinterfaces for internal VLANs and one interface is connected to ISP and is NAT'ing internal networks with dynamic NAT. Also I have global ACL's which permit traffic between a part of vlans and deny traffic between another VLANs. Another option which is set on ASA is "same-security-traffic permit inter-interface". In this case it seems that all is working good. But if I disable "same-security-traffic permit inter-interface" the traffic between internal subinterfaces (with the same security level) is not passing although an explicit ACL which permit traffic between these interfaces is configured in global.
I was not able to find the documentation about ACL vs "same-security-traffic permit inter-interface", could somebody tell me - does
"same-security-traffic permit inter-interface" have precedence over explicit ACL ?
Re: ASA same-security-traffic permit inter-interface vs ACL
In the old days of the PIX it was a feature. If two interfaces have the same security-level, then they are separated and can't communicate with each other regardless what else is configured. Later when the FWSM was introduced it was possible to have Firewalls with more then 101 interfaces. A feature was needed to overwrite this functionality. This behavior is still valid, but of course we can disable this function with the mentioned command. So yes, the command has precedence over an ACL.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...