Software Consulting Engineering Technical Leader at Cisco. Systems & network administration, Python, Ansible, DevOps, CI/CD, and much more! Tweets are my own
Raleigh, NC
Joined January 2016
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- Followers3.2K
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Christopher Hart retweeted
It took us a while to deliver this (and, you guessed it, this was not entirely a technical problem). But we finally made it. Free CML tier, available w/ the 2.8 release. I am super glad and proud of the entire team for pulling this off! #ciscomodelinglabs #networksimulation 🍻
Massive News! Cisco Modeling Labs (CML) has a FREE tier!
Download for free here: davidbombal.wiki/freecml
#SponsoredbyCisco #ccna #ccnp #ccie #cisco #network #router #switch #firewall #study #career #Motivation @Cisco @LearningatCisco
Christopher Hart retweeted
Massive News! Cisco Modeling Labs (CML) has a FREE tier!
Download for free here: davidbombal.wiki/freecml
#SponsoredbyCisco #ccna #ccnp #ccie #cisco #network #router #switch #firewall #study #career #Motivation @Cisco @LearningatCisco
Christopher Hart retweeted
🛠️ Wireshark Tip: Make a Button for That!🛠️
🔍Create display filter buttons
📚Organize them under headings
✅Improve your workflow instantly
Check out the step-by-step guide and start enhancing your Wireshark toolset!
chappell-university.com/post…
#Wireshark #NetworkingTools
Christopher Hart retweeted
pyATS Tip: Customize SSH directly within the pyATS testbed using ssh_options. Ideal when needing to alter the algorithms used when connecting to older devices.
Here is an example 👇
Great, quick article from @packetcoders on how to use Python's itertools.product() function to make nested for loops in #Python easier to read!
packetcoders.io/how-to-flatt…
Genuine question: If a firewall doesn't respond to pings by default, is it compliant w/ RFC 1122?
Section 3.2.2.6 of RFC 1122 says:
Every host MUST implement an ICMP Echo server function that receives Echo Requests and sends corresponding Echo Replies.
datatracker.ietf.org/doc/htm…
But reading this clause carefully, I feel like "MUST implement an ICMP Echo server function" is meaningfully distinct from "MUST send corresponding Echo Replies after receiving Echo Requests".
Christopher Hart retweeted
Sounds like Intel has realized it's in trouble. Never underestimate The Innovator's Dilemma. apenwarr.ca/log/20201227
Christopher Hart retweeted
A while back I asked you why we didn't have anycast gateways before #VXLAN I received a lot of great responses. Here's my take on it. Happy reading!
lostintransit.se/2024/06/25/…
Adding on to this - even on very busy interfaces (10/40/100Gbps) you can combine ping's size argument with detailed interface counters from network devices to confirm whether traffic flows through network device interfaces or not.
⬇️🧵
Above, we send 100K pings with a 600 byte packet size. We expect the "512 to 1023 bytes" bucket to have a counter *around* 100K (ideally exactly 100K, but +/- a few is fine).
Sure enough, after the ping completes, if we check counters again, we can see ~100K in the bucket.
Christopher Hart retweeted
#YesterdaysCCNAQuestion
The answer is Management Plane
Data plane deals with traffic as it traverses the network.
Control plane handles processes destined for the network device.
@_ChrisJHart has a great post on it. tinyurl.com/yd8dtzs7
Here's another teaser from the upcoming course! This GIF'd slideware walks through how Gratuitous ARP (GARP) works using a practical, everyday example involving hypervisors and virtual machines.
If you use VMware/Nutanix/etc. or HSRP/VRRP, you've likely seen this in action!
Work-in-progress sneak peek from an upcoming @pluralsight course I'm developing on analyzing network protocols in Wireshark!
This course includes a 3-minute speedrun refresher on how Ethernet works, with this GIF'd slideware summarizing multicast communication.
Christopher Hart retweeted
Just a heads up #Ansible folks. It's not you...
Ansible Galaxy seems to be down right now.
Happy Friday! 🤖🔥
forum.ansible.com/t/ansible-…
