- DMVPN (4)
- IPv6 (1)
- MPLS (1)
- Network Automation (19)
- Network Security (4)
- Network Services (8)
- Quality of Service (2)
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recent posts
- BGP Security best Practices for ISPs and Enterprise Networks
- Protecting BGP with Filtering and RPKI
- BGP Security
- Security Architecture: More Than Just Firewalls
- DMVPN Dual Hub Dual Cloud – Full Redundancy Design
- DMVPN Dual Hub Single Cloud: Hub Redundancy Without Losing Path Control
- DMVPN Single Hub Dual Cloud: Why Redundancy Does Not Always Mean Optimal Failover
- DMVPN Single Hub Single Cloud: Design Behavior Across Phase 1, 2 and 3
- L3VPN is not just about labels, MP-BGP, or VRFs
- IPv6 Prefix Delegation and SLAAC
- WFQ, CBWFQ and LLQ Explained in a Practical Way
- How Traffic is Classified, Marked, and Queued
- NAT
- Proxy ARP
- DNS and HTTP GET with IP SLA
- Cisco IRB (Integrated Routing and Bridging)
- GLBP Weighting
- DNS Server on Cisco IOS
- DHCP Proxy over PPP
- ARP authorized
- QoS in Cisco SD-WAN
- Application-based traffic steering And AAR
- Creating Extranets and Access to Shared Services
- Enforcing Security Perimeters with Service Insertion
- Cisco SD-WAN TLOC Extension
- Cisco SD-WAN Security Features
- Traffic Engineering at Sites with Multiple Routers
- Isolating Guest Users from the Corporate VPN
- Cisco SD-WAN Hub-and-Spoke Topology
- Cisco SD-WAN Onboarding
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In modern networks, we usually separate Layer 2 switching and Layer 3 routing clearly. However, in some legacy or special scenarios, a router may need to do both bridging and routing at the same time. This is where Integrated Routing and Bridging (IRB) comes in. Integrated Routing and Bridging (IRB) allows a Cisco router to…
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When we talk about First Hop Redundancy Protocols, many engineers immediately think about HSRP or VRRP. These protocols provide gateway redundancy, but they do not natively offer load balancing across multiple active gateways in the same way as GLBP. GLBP is a Cisco proprietary protocol that allows multiple routers to share the role of forwarding…
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Normally, when we think about DNS, we think about dedicated DNS servers. But Cisco IOS routers can also provide useful DNS features. In this scenario, I built a small lab to test how a router can act as: The lab contains two DNS servers and two clients. One of the clients also works as a…
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In this lab, I wanted to analyze a very specific use case: How can a router connected over a PPP serial link receive its IP address dynamically from a DHCP server that is not directly attached? What makes this lab interesting is that the DHCP client is connected through a PPP serial interface, not through…
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In this lab, I wanted to analyze the behavior of the Cisco IOS interface command arp authorized. The idea behind this feature is that the router should not rely on normal dynamic ARP learning on that interface. Cisco documents this behavior by stating that arp authorized stops dynamic ARP on the interface. Because of that,…
