Qemu ASAv Appliance as Personal Firewall on Linux
The article discuss how to run Cisco Adaptive Security Virtual Appliance (ASAv) on KVM hypervisor as your personal firewall. Since ASAv version 9.3.2-200, Cisco supports deploying ASAv using Kernel-based Virtual Machine (KVM). Thanks for the support of KVM hypervisor, ASAv can be deployed in a very easy manner on Linux and any mysterious hacks is needed anymore.
Unfortunately until a valid license file is installed, ASAv throughput is limited to 100 Kbps. So far I have not found a way how to bypass this limitation as Cisco does not provide any evaluation licence as they offer for their CSR100v IOS-XE router. I also found out that ASAv keeps rebooting when Qemu is started without enabled KVM option. It limits deployment of ASAv Qemu images on Linux/FreeBSD as KVM is available for these operation systems only. Windows users should download and install ASAv edition for VMware hypervisor.
Software Requirements
• Linux x86_64 with installed Qemu and KVM
• Cisco ASAv Virtual Appliance - Qemu image asav932-200.qcow2 or later
HardwareRequirements
• CPU with VT-X or AMD-V hardware virtualization support
• 2GB RAM dedicated for ASAv virtual machine
1. ASAv Installation
Installation does not requires any special skills and takes only one reboot. Start the ASAv virtual machine Continue reading
Dynamically monitor interfaces with Nagios
When you’re setting up your monitoring configuration for Nagios or compatible software it can be a hassle to decide which interfaces you actually want to monitor. Well rather how to monitor those interfaces. The nm_check_admin_up_oper_down plugin (part of Nelmon) checks the configuration of your network devices and reports a problem if you’ve indicated that the interface should be up.
VRF Race Condition
A while ago I observed an interesting problem due to a routing misconfiguration. An asymmetric route was introduced across two discrete switches/routing instances. The route was then imported in a separate location.
Quick and dirty network diagram
When I began troubleshooting I was under the impression that the importer preferred one route over another because of admin distance or some other metric, or perhaps it was some sort of BGP esoterica you’d only encounter if you were using VRFs and MP-BGP to learn routes. However, the truth was probably something more prosaic.
Both routes were static routes. This meant their learning mechanism across importers was the same. The reason the importer preferred one route over another was probably due to one entering the routing table before the other.
Dynamically monitor interfaces with Nagios
When you’re setting up your monitoring configuration for Nagios or compatible software it can be a hassle to decide which interfaces you actually want to monitor. Well rather how to monitor those interfaces. The nm_check_admin_up_oper_down plugin (part of Nelmon) checks the configuration of your network devices and reports a problem if you’ve indicated that the interface should be up.
Continue reading
Using Git with GitHub
Building on my earlier non-programmer’s introduction to Git, I wanted to talk a little bit about using Git with GitHub, a very popular service for hosting Git repositories. This post, in conjunction with the earlier introductory post on Git, will serve as the basis for a future post that talks about how to use Git and GitHub to collaborate with others on an open source project hosted on GitHub.
If you aren’t familiar with Git and haven’t yet read the earlier introductory post, I strongly recommend reading that post first.
Recall that Git is a distributed version control system (DVCS), and is designed to operate in such a way that full copies of repositories exist on multiple systems. This means you (as a single user) might have multiple copies of a repository across multiple systems. So how does one keep these repositories in sync? Generally, this would be handled via the use of a “server-side” repository to which the various repository clones are linked via a Git remote. This server-side repository might be hosted on an internal server or on a public server, and you may be connecting to it using the Git protocol, SSH, or HTTP(S). You Continue reading
2015 is all about SDN WAN
The technology that gives me a “nerd hard-on” this month is SDN WAN. Here is why.
The post 2015 is all about SDN WAN appeared first on EtherealMind.
Configuring Syslog and SNMP on a Cisco Device
by Kevin Dooley, originally published on the Auvik blog There are two common ways to get management information about your network devicesCoding Basics: Python in Visual Studio
Python on Windows with Visual Studio
Whilst I’m an OSX and Linux fan, Windows is a key operating system in any enterprise and developing network applications in a Windows environment is also an important topic to cover off. Visual Studio (VS) is a Windows IDE (Integrated Development Environment) which will also soon be available for OSX (at the time of writing, it isn’t released). Whilst I’ve brushed over this previously, this post is a quick guide on how to setup a very easy to use environment to play with Python. This is not however an in depth tool chain guide. This is a 101 post but will be enough for most people to get to grips with Python who use Windows. Let’s face it, you don’t really want to be sitting on the command line doing this do you and Eclipse is not to everyone’s taste, especially if you have prior experience coding with .net for instance.
- Install the free version of Microsoft’s Visual Studio found here
- Install Python 3.x (or 2.x depending on your reasons) found here
- Install the Python tools for Visual Studion found here
I install both Python 2.x and 3.x as you Continue reading
Networking FAQ 4: Fundamentals
- At what OSI layer does protocol X operate?
- What's the difference between a router and a multilayer switch?
- What's the difference between forwarding and control planes?
- What's the difference between MTU and MSS?
- What's the difference between a VLAN interface and a BVI?
- How do tunnel interfaces work?
- What do NAT terms like "inside local" mean?
- Can I use the network and broadcast addresses in a NAT pool?
- Why do we need IP addresses? Can't we just use MAC addresses for everything?
- Does QoS provide more bandwidth?
Networking FAQ 4: Fundamentals
- At what OSI layer does protocol X operate?
- What's the difference between a router and a multilayer switch?
- What's the difference between forwarding and control planes?
- What's the difference between MTU and MSS?
- What's the difference between a VLAN interface and a BVI?
- How do tunnel interfaces work?
- What do NAT terms like "inside local" mean?
- Can I use the network and broadcast addresses in a NAT pool?
- Why do we need IP addresses? Can't we just use MAC addresses for everything?
- Does QoS provide more bandwidth?
Networking FAQ 4: Fundamentals
- At what OSI layer does protocol X operate?
- What's the difference between a router and a multilayer switch?
- What's the difference between forwarding and control planes?
- What's the difference between MTU and MSS?
- What's the difference between a VLAN interface and a BVI?
- How do tunnel interfaces work?
- What do NAT terms like "inside local" mean?
- Can I use the network and broadcast addresses in a NAT pool?
- Why do we need IP addresses? Can't we just use MAC addresses for everything?
- Does QoS provide more bandwidth?
Netscreen Packet Capture – Snoop
I’ve worked with Netscreens for a few years now, starting with ScreenOS version 5.x, and when troubleshooting I had always been pointed towards debug flow as the way to see what was going on. I suspect many of you have also been taught:
clear dbdebug flow basic- (wait for packets you wanted to capture)
undebug allget db stream(to view output)
This is definitely helpful for rule debugging but for simple packet capture is a bit over the top, which is where the snoop command comes in.
Snoop
To be clear, snoop won’t tell you anything about what decisions the firewall made about the packets, but it’s a simple way to see the actual traffic. Here’s an example of the output produced by snoop:
19944926.0: ethernet2/1(o) len=206:0010dbff2070->00005e000101/8100/0800, tag 1872
1.4.63.82 -> 1.15.18.27/17
vhl=45, tos=00, id=13096, frag=0000, ttl=64 tlen=188
udp:ports 500->500, len=168
00 00 5e 00 00 01 00 10 db a1 27 a1 81 00 07 50 ..^........p....
08 00 45 00 00 bc 33 28 00 00 40 11 b6 18 01 04 ..E...3([email protected]
3f 52 01 0e 12 1b 01 f4 01 f4 00 Continue readingIPv6 Renumbering – Mission Impossible?
In one of the discussions on v6ops mailing list Matthew Petach wrote:
The probability of us figuring out how to scale the routing table to handle 40 billion prefixes is orders of magnitude more likely than solving the headaches associated with dynamic host renumbering. That ship has done gone and sailed, hit the proverbial iceberg, and is gathering barnacles at the bottom of the ocean.
Is it really that bad? Is simple renumbering in IPv6 world just another myth? It depends.
Read more ...Using GNS3 for Basic Network Security Testing
(The original idea for this post came from a post my blog, “The Console Port,” which you can find atFabric visibility with Arista EOS
A leaf and spine fabric is challenging to monitor. The fabric spreads traffic across all the switches and links in order to maximize bandwidth. Unlike traditional hierarchical network designs, where a small number of links can be monitored to provide visibility, a leaf and spine network has no special links or switches where running CLI commands or attaching a probe would provide visibility. Even if it were possible to attach probes, the effective bandwidth of a leaf and spine network can be as high as a Petabit/second, well beyond the capabilities of current generation monitoring tools.The 2 minute video provides an overview of some of the performance challenges with leaf and spine fabrics and demonstrates Fabric View - a monitoring solution that leverages industry standard sFlow instrumentation in commodity data center switches to provide real-time visibility into fabric performance.
Fabric View is free to try, just register at http://www.myinmon.com/ and request an evaluation. The software requires an accurate network topology in order to characterize performance and this article will describe how to obtain the topology from a fabric of Arista Networks switches.
Arista EOS™ includes the eAPI JSON-RPC service for programmatic monitoring and control. The article Arista Continue reading
Untangle Scrutinized : Deep Dive into Untangle’s Features
This article is a followup to : Setting Up Untangle NGFW in a GNS3 Environment. In this one we take a deep dive into Untangle’sNFD9 Prep: SD-WAN
Software Defined WAN, or SD-WAN, looks to be a theme of Network Field Day 9, with presenters such as CloudGenix and VeloCloud showing us their offerings. At first glance, SD-WAN sounds pretty compelling. Who wouldn’t want to slash their WAN OpEx? How do these solutions work, and do they have legs? I’m hoping to find out.
NB: I’ve lumped CloudGenix & VeloCloud together under the heading of SD-WAN. I’m not saying that they are the same though – I don’t yet have enough information about them to fully understand the similarities and differences. I’m sure I’ll know more in a couple of weeks!
What’s SD-WAN all about?
SD-WAN is about applying concepts of SDN to WAN networks. The goals are to increase flexibility and reduce WAN costs. This can be achieved through transport independence, dynamic path management, and better config management.
Historically we used private WAN circuits – leased lines, MPLS, etc. These had great SLAs, but the monthly costs were huge. The bandwidth was low, but guaranteed. Now that many places have access to high-speed Internet tails, it’s a lot harder to justify that cost. It’s very tempting to run IPSec VPNs across Internet links instead.
Those consumer Continue reading
Device Alias on Cisco MDS
It is definitely not convenient to configure a zone or any CFS application using WWpN. 20:ab:3d:2c:4f:89:fa:ab is not very human readable and it is definitely not efficient to keep traces of the WWpN in your MDS configuration. Device-alias is a proprietary feature created by Cisco to make your life much easier. It will map an […]Creating a Network Community for the Network’s New Operational Models
The way in which networks are configured, deployed, and managed is changing. The network industry is in a shift from managing devices box by box via the CLI to having more centralized ways to manage and deploy devices. While the CLI isn’t going away anytime soon, we can look at the two operational models that are gaining traction within the network community.
SDN Controllers
SDN controllers do two major things that increase operational efficiencies. They offer a central point of management and visibility for the network team, but also offer a single point of integration for 3rd party systems – these systems could be anything from cloud management platform, monitoring or automation systems, to native business applications. Note: even when there are controllers being used by a human, there is risk. There is the risk of clicking the wrong button, forgetting the order of operations of which buttons needs to be clicked, etc. This doesn’t go away. Change control windows still have risk.
DevOps for Networking
We’ve also seen an increased amount of focus on the intersection of DevOps and networking. I’m really referring to DevOps automation tools and the network. For Continue reading
SDN controllers do two major things that increase operational efficiencies. They offer a central point of management and visibility for the network team, but also offer a single point of integration for 3rd party systems – these systems could be anything from cloud management platform, monitoring or automation systems, to native business applications. Note: even when there are controllers being used by a human, there is risk. There is the risk of clicking the wrong button, forgetting the order of operations of which buttons needs to be clicked, etc. This doesn’t go away. Change control windows still have risk.
DevOps for Networking
We’ve also seen an increased amount of focus on the intersection of DevOps and networking. I’m really referring to DevOps automation tools and the network. For Continue reading