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2008-10-27

Using MAC Access-lists

We ran into this today, and, though I knew it existed, I never actually saw it in the wild.  I’m talking about MAC access-lists. In the example setup, we have a DMZ off of a firewall that contains a whole mess of servers — email, web, ftp, etc.  These should all be in the DMZ […]

2008-06-12

ACLs and HSRP, BGP, OSPF, VRRP, GLBP…

Here’s a handy list of ACL entries to allow your devices to speak routing protocols, availability protocols, and some other stuff. We’ll assume you have ACL 101 applied to your Ethernet inbound; your Ethernet has an IP of 192.168.0.1. BGP : Runs on TCP/179 between the neighbors access-list 101 permit tcp any host 192.168.0.1 eq […]

2008-03-12

Commenting Access-lists

There’s a very-overlooked feature of access-lists — the remark. Yes, this is very basic, but it’s worth mentioning, as it has saved me anguish time and time again. I use remarks to document each line of an ACL (on IOS, PIX, FWSM, ASA, etc.) so that when I go back later, I actually know what […]