05-04-2012 10:43 AM - edited 03-11-2019 04:02 PM
Hi Experts
what is the technical difference betwen:
access-list acl permit tcp host 10.10.10.10 eq 80 any ?
and
access-list acl permit tcp host 10.10.10.10 any eq 80 ?
it confuses a little bit
thanks
jamil
05-04-2012 10:49 AM
Hi Ibrahim,
Source IP 10.10.10.10 source port 80 -> any IP destination any port destination
access-list acl permit tcp host 10.10.10.10 eq 80 any ?
Source IP 10.10.10.10 source port any -> any IP destination port destination 80
access-list acl permit tcp host 10.10.10.10 any eq 80 ?
Dan
05-04-2012 10:52 AM
Jamil,
The first one indicates that the packet from 10.10.10.10 will come with a source port 80. Since TCP connection start with a random source port, the ACL mostlikely is not going to be hit. In case of a Router, where they are more packet wise than connections, it may work, but for an ASA it wont, because a connection needs to be established prior a response on well known port is received.
The second one is more common, it usually allows connection to well known ports for the first SYN packet (in case of TCP connections). That will allow a connection establishment on the ASA firewall, then the return packets will be allowed preventing you the need of configuring ACLs with source ports.
Mike
05-04-2012 11:41 AM
Thanks for ur reply guys
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