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How Cisco ESA treats email traffic
I was working with Cisco ESA (previously - Ironport) lately and would like to write down some notes about how it works (at least the basics). I've already covered spam and antivirus testing techniques in a previous post. Here I'll try to walk through the message filtering steps performed by a Cisco ESA appliance. email, antivirus, ironport, esa, smtp, antispam, ciscoHow do I test if my email antispam and antivirus work?
It might come in a greenfield antispam / antivirus deployment or during an audit that one needs to make sure that the protection (against spam or viruses) is enabled (N.B.: measuring protection efficiency is a completely different problem) and the configured policies are applied as expected.As with any program testing, for that task we need sample ( Read more... )Cisco UCS HyperFlex FE class notes
Recently I attended a two-day class on Cisco HyperFlex by Tomaz Klancnik from NIL. It was quite interesting and packed with information about this new Cisco's system. Here are the notes I took during the lectures and the labs.General Notes about Cisco HyperFlexNot developed internally; Not a vmware, lecture_notes, storage, hyperflex, cluster, virtual, cisco, hypervisor, ucsPer-VLAN Spanning Tree Plus (PVST+)
Spanning-tree protocol is one of the oldest ways to ensure loop-free topology of an ethernet network. Why we need it, where we need it and how it works is the subject of today's recap post.
http://askbow.com/2015/07/03/per-vlan-spanning-tree-plus-pvst/Etherchannel, LAG, portchannel and friends
An EtherChannel is a way to use multiple physical interfaces as a single logical one. That logical one appears as a single interface to MAC table, STP and management plane. That solves two main concerns: it adds bandwidth and it prevents STP from considering several parallel links a loop, thus preventing it from being blocked. ethernet, ccie, lag, pagp, stp, basics, switching, lacp, cisco, l2Recap: VLAN Trunking Protocol
Cisco VTP - the VLAN Trunking Protocol is a management tool for large L2 deployments.It provides a simple way to synchronize VLAN names and numbers across Cisco switching infrastructure, also automates some traffic optimizations (the VLAN pruning).http://askbow.VLANs & Trunking
A quick recap: Virtual LANs and Trunking in Cisco Ethernet switches. There are different VLAN ranges, switchport modes and some ways to manage all that.
http://askbow.com/2015/06/22/vlans-trunking/Routing Protocols over On-Demand circuits
This is the second post about Demand in Routing. In the first post I covered some common demand-related points and Cisco On-Demand Routing. In today's post I write a little about Routing Protocols and their behavior over on-demand circuits.http://Making sense of all the demands in routing
Apparently, there are several very distinct topics in routing which have the word "demand" in them. First, there is Cisco On-Demand Routing quasi-protocol, and then there are on-demand circuits which routing protocols must treat differently. Last but not least, the on-demand circuits are used for Routing Backup. routing, ccie, routing protocols, default route, ciscoVRF Lite basics
Sometimes while you do routing, you want to do it in a destination-based way and also differentiate routing for different sub-autonomous systems in your AS. Well, such behavior can be enforced by PBR, but it is not that scalable and it lacks some of the nicer things dynamic routing protocols bring to the table. Enter Virtual Routing and Forwarding ( Read more... )