Cisco Adaptive Security Appliance, the stateful firewall platform that has anchored enterprise perimeters for two decades and is now being succeeded by Secure Firewall (FTD). Articles tagged ASA cover security levels, NAT 8.3+ and twice NAT, ACLs, AnyConnect SSL and IKEv2 VPN, site-to-site IPsec, failover, packet-tracer, hardening, and ASAv 9.x lab walkthroughs.
Cisco removed Clientless SSL VPN (WebVPN) from the ASA in 9.17. Real 9.24 CLI proof, and the Secure Client remote-access VPN that replaced it.
Enable ASDM on a Cisco ASA 9.24, hit the image-not-set gotcha, and get the honest 2026 verdict on the Java GUI versus the CLI.
Endpoint versus pass-through on the Cisco ASA: inspect ipsec-pass-thru, NAT-T on UDP 4500, and the classic Phase 1 up, Phase 2 down failure.
Map IKEv1 to IKEv2 on the Cisco ASA command by command, then cut a live site-to-site tunnel over without an outage.
A real LAN-to-LAN IKEv2 tunnel from a Cisco ASA to an IOS XE peer, verified with show vpn-sessiondb from a live CML capture.
Every ACL you have ever written on a firewall operates on IP: source address, destination address, port, protocol. A routed
We learned the first lesson of transparent-mode firewalls the hard way, live, mid-command. Typing firewall transparent on our
Some of the hardest firewall tickets sound like ghost stories. A connection that works fine between two hosts dies the
This is where the ASA stops being a Layer 4 gate and starts reading your web traffic. In this article
A stateful firewall that only reads Layer 3 and Layer 4 headers is half a firewall. It can decide whether
If you have ever stared at an ASA configuration and wondered how a single firewall applies HTTP inspection here, a
The Cisco ASA offers a whole family of high-availability and scale features: failover in two flavors, redundant interfaces, EtherChannel,