Understanding ‘transport output’ and ‘access-class’
Several years ago I wrote an article called The Elusive “access-class out” Command. My primary goal was to help CCNA students understand both the behavior of and placement of this command. My friend Anthony Sequeira done a great job in the video that is also shown in my original post. Today, I want to share another command and expand on there behavior.
For all of the demonstrations in this article, the following topology will be used. The router named iosv-2 will be the primary focus and the only place changes will be made.
Topology
Backing up for a moment, there are a couple of messages that might be displayed when an IOS device blocks outbound telnet or ssh sessions from the current exec session. These are demonstrated with a quick configuration of an transport output and access-class restriction.
//the first error is unique depending on //if ssh or telnet is being used iosv-2(config)line con 0 iosv-2(config-line)#transport output none iosv-2(config-line)#do telnet 192.168.0.3 % telnet connections not permitted from this terminal iosv-2(config-line)#do ssh -l cisco 192.168.0.3 % ssh connections not permitted from this terminal //now we can re-enable all the protocols //and demonstrate the other error message iosv-2(config-line)#transport input all iosv-2(config-line)#access-list Continue reading
GigaSpaces Unleashes New Version of Cloudify Orchestration
It includes plug-ins for all major cloud platforms.
Worth Reading: Independence from L2 data centers
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NGMN to Write the 5G Trial Rulebook For Mobile Operators
The alliance will also compare 5G technologies and support standardization.
NetBox v1.1.0 Released
One year ago today, I made the first commit to a repository named "netbox" hosted internally at DigitalOcean. It was the first iteration of a tiny little app I scratched together using the Django Python framework to track IP prefix utilization. A year later, NetBox has grown into an extensive tool that we use to track IPs, racks, devices, connections, circuits, and even encrypted credentials. And I'm happy to say that it's now open source!
NetBox v1.1.0 Released
One year ago today, I made the first commit to a repository named "netbox" hosted internally at DigitalOcean. It was the first iteration of a tiny little app I scratched together using the Django Python framework to track IP prefix utilization. A year later, NetBox has grown into an extensive tool that we use to track IPs, racks, devices, connections, circuits, and even encrypted credentials. And I'm happy to say that it's now open source!
NetBox v1.1.0 Released
One year ago today, I made the first commit to a repository named "netbox" hosted internally at DigitalOcean. It was the first iteration of a tiny little app I scratched together using the Django Python framework to track IP prefix utilization. A year later, NetBox has grown into an extensive tool that we use to track IPs, racks, devices, connections, circuits, and even encrypted credentials. And I'm happy to say that it's now open source!
Absorbing DDoS with Communities
Distributed Denial of Service attacks can damage your business—and they can be difficult to manage or counter. While there are a number of tools available to counter DDoS attacks, particularly in the commercial space, and there are a number of widely available DDoS protection services, sometimes it’s useful to know how to counter a DDoS on your own. One option is to absorb attacks across a broader set of inbound nodes. Let’s use the network below to illustrate (though often the scale needs to be quite a bit larger for this solution to be useful in the real world).
Assume, for the moment, that the attacker is injecting a DDoS stream from the black hat, sitting just behind AS65004. There are customers located in AS65001, 2, 3, 4, and 5. For whatever reason, the majority of the attacker’s traffic is coming in to site C, through AS65003. Normally this is a result of an anycast based service (such as active-active data centers, or a web based service, or a DNS service), combined with roughly geographical traffic patterns. Even a DDoS attack from a mid sized or large’ish botnet, or reflection off a set of DNS servers, can end up being Continue reading