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New Member

PIX & the OSI model

I'm reading a book about PIX, and it claims that PIX protects layer 2-7. I can only find info on how it protects layers 3,4,& 7. Do any of you experts know any specifics about how it protects each layer? Here's what I have so far...

Application layer: Proxies check for RFC compliance.

Presentation layer: ??

Session layer: ??

Transport layer: TCP/UDP ports

Network layer: IP addresses

Data Link layer: ?? (can it check frames?)

Physical layer: ??

2 REPLIES
Cisco Employee

Re: PIX & the OSI model

Layer 2 is I guess just the fact that it checks the frames for CRC errors and valid checksums.

The PIX keeps track of the ACK and SEQ numbers in TCP frames to make sure they're part of an existing session, I gues that could refer to the Session Layer.

Presentation Layer I have no idea.

Application layer is the "fixup"'s that are turned on in the PIX, allowing for protocol-specific modifications and checks to application layer data.

New Member

Re: PIX & the OSI model

Just to add to the Glenn's comment.

TCP/IP protocol suite doesn't respect ISO model. In the TCP/IP model, layer 5 & 6 are absents. It's the reason you will never find specific informations about layer 5 & 6.

Regards,

Ben

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