Enable a RESTful ASA API

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close up photography of sleeping tabby cat Starting from ASA 9.3(2) and onward the 5500-X hardware supports a RESTful API as an additional method for configuration/monitoring ASA hardware. Infrastructure as code as they call it, not anything new but I was reading a post that Ivan Pepelnjak wrote and as he points out there are two types of styles when we are dealing with IaC, the data model or CRUD. When reading information about the ASA RESTful API it was interesting what the ASA falls into, CRUD is the method it uses and although this method works, I have similar feeling to what Ivan posted, it wonders me if this is really a step forward into IaC. In this post we’ll go through the steps to enable it and you can be the judge, does this RESTful API help? Continue reading →

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Verifying DNS Lists – FMC

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We are back with another post about Cisco’s Firepower Management Center and this time we are working with the DNS list which if you have a protect license you can have your Firepower modules or your FTD (Firepower Threat Defense) devices look at DNS requests and deny requests if they are malicious. These have to be applied on your access control policy to be able to use it and in this post we are going verify some of the domain names that are in this lists. Continue reading →

Installing a GNS3 Server

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gns3_logoAlthough GNS3 can run local on your computer and you can use VMware Workstation and have the GNS3 appliance. I found it much more stable and predictable to run GNS3 on a dedicated server. Using this type of installation, all the projects, and images are stored on the GNS3 server, so I can install the GNS3 client any computer and get access to the same projects I was working on. You can also have multiple people working on different projects that are on the same server. I find that neat for educational use or if you where helping someone with a project. In this post I’ll walk though the steps needed to set up a GNS3 server.

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Cisco FTD Standalone

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No management centers here, sometimes a standalone firewall is all you need. In this post I have a FTD appliance and there really isn’t a need tie this into Cisco’s Firepower Management Center. So we’ll configure appliance in standalone mode and go through the initial first steps that are required to get it online and walk through Firepower Device Manager. If you worked with Cisco FMC you’ll find its pretty similar, so with introductions out-of-the-way let’s get started!

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Too Many TCP Resets

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So, recently we enforced some firewall rules on a new environment, we did testing of the environment and everything was working as expected. In about 24 hours a lot of traffic from the web infrastructure was being denied and it continued, at first glance it looked like return traffic was being dropped, the web servers were sourcing at port 443 and the destination ports were using dynamic ports (RFC 6335)

No user or application problems were reported when we enforced rules, and we waited additional days to see if anything came up. Nothing came up, the only thing was a spike in amount of syslog messages of dropped traffic coming from the web servers. So from that point it really wasn’t an issue, but I thought it would be interesting to see what was going on. Continue reading →