[comp.protocols.tcp-ip] Access Control Lists

guri@oakhill.UUCP (Gurvinder Singh Ahluwalia) (06/05/90)

At what stage is ACL verification done for a session?
[Of course, it is done when a session is established]. 
I wouldn't like to think that every packet has to be 
ACL-verified. Does that sound right? If so, how are
packets decided "go/no-go" across cisco ONCE a session
has been established? How does the cisco relate to 
the concept of a session (for subsequent packets) AFTER 
a session has been authenticated at ACLs? Doing a per
packet ACL-verification sounds like tremendous overhead.

Secondly, what kind of search algorithm is implemented on
ciscos for an optimum and effective ACL search?

Gurvinder Ahluwalia
Phone		: 512/891-3310
Internet	: guri@apogee.sps.mot.com		(PREFERRED)
UUCP		: ...!oakhill!apogee@cs.utexas.edu

ssw@cica.cica.indiana.edu (Steve Wallace) (06/05/90)

In <3362@apogee.oakhill.UUCP> guri@oakhill.UUCP (Gurvinder Singh Ahluwalia) writes:


>At what stage is ACL verification done for a session?
>[Of course, it is done when a session is established]. 

IMHO, the cisco should have no notion of a session.  When it's
talking IP, everything is connectionless.  The cisco has to
examine every packet to decide where to route it.  Doesn't seem
like too much more overhead to check an ACL at the same time.
One would assume that they have some-sort-of hash table.

Of course, in the European OSI world things are different.


Steven Wallace
Indiana University
wallaces@ucs.indiana.edu