Blog Posts in 2009

December 2009

• ITU and Internet Billing: It’s a Déjà-Vu All Over Again (21 Dec 2009)
• Send a SNMP trap from an EEM applet (18 Dec 2009)
• Next-generation IP services (17 Dec 2009)
• IPv6 is not ready for residential deployment (16 Dec 2009)
• HQF: Truly Hierarchical Queuing (15 Dec 2009)
• Book review: Cisco Routers for the Desperate (11 Dec 2009)
• The sorry state of our industry (10 Dec 2009)
• Load Sharing 101 (with References) (09 Dec 2009)
• Ten steps of small LAN design (08 Dec 2009)
• Lies, damned lies and product marketing (07 Dec 2009)
• Certifications and the hiring process (04 Dec 2009)
• iSCSI and SAN: Two Decades of Rigid Mindsets (03 Dec 2009)
• IPv6 in the campus but not in the Data Center? (02 Dec 2009)

November 2009

• HQF: intra-class WFQ ignores the IP precedence (26 Nov 2009)
• Twitter (24 Nov 2009)
• Dual-stack PPP requires two separate sessions? (24 Nov 2009)
• “ip ospf mtu-ignore” Is a Dangerous Command (23 Nov 2009)
• Who Needs IPv6? (20 Nov 2009)
• Detect short bursts with EEM (18 Nov 2009)
• HQF: intra-class fair queuing (16 Nov 2009)
• Detect DoS Attacks with EEM (13 Nov 2009)
• IPv6 in the Data Center: is Cisco ready? (12 Nov 2009)
• First HQF impressions: excellent job (11 Nov 2009)
• Solution: Bandwidth+Police actions in CB-WFQ (10 Nov 2009)
• ITU: Grabbing a Piece of the IPv6 Pie? (09 Nov 2009)
• Challenge: CB-WFQ Bandwidth+Police behavior (06 Nov 2009)
• Off-topic: universal engineers (05 Nov 2009)
• CB-WFQ misconceptions (04 Nov 2009)
• Book review: Foundation of Green IT (02 Nov 2009)

October 2009

• IPv6-capable or IPv6-ready: is it enough? (28 Oct 2009)
• Followup: What’s wrong with the Zone-Based Firewalls book (27 Oct 2009)
• What’s your take on Alcatel-Lucent IP+Optical integration? (26 Oct 2009)
• IOS packaging: Moore’s Law Won (23 Oct 2009)
• Help appreciated: what’s wrong with my Zone-based Firewalls book? (20 Oct 2009)
• What went wrong: TCP lives in the dial-up world (19 Oct 2009)
• Fantastic DDoS protection: it’s getting worse (14 Oct 2009)
• Follow-up: Interface Default Route (12 Oct 2009)
• My Stupid Moments: Interface Default Route (09 Oct 2009)
• DHCP Client Address Change Detector (07 Oct 2009)
• Will they ever start using their brains? (06 Oct 2009)
• SSH RSA authentication works in IOS release 15.0M (05 Oct 2009)
• IOS release 15.0 (03 Oct 2009)
• IOS Fossils: Classful OSPF Redistribution (02 Oct 2009)

September 2009

• Follow-up: P-to-P router encryption (30 Sep 2009)
• DHCP Logging in Cisco IOS Is a Nightmare (28 Sep 2009)
• Deploying IPv6 in Enterprise Networks (25 Sep 2009)
• Encrypting P-to-P-router traffic (23 Sep 2009)
• The tunneling Kool-Aid (21 Sep 2009)
• Fishing for free information: the ultimate experience (18 Sep 2009)
• Carrier Ethernet service from customer’s perspective (17 Sep 2009)
• Expired DHCP Lease Bounces the Interface (16 Sep 2009)
• Back from vacation (15 Sep 2009)
• Display the rejected BGP routes (03 Sep 2009)

August 2009

• What went wrong: SCTP (31 Aug 2009)
• Disable Flapping BGP Neighbors (28 Aug 2009)
• Do Not EVER Run OSPF or IS-IS With Your Internet Customers (26 Aug 2009)
• What Went Wrong: the Socket API (24 Aug 2009)
• Turn a switch into a hub … the Microsoft way (21 Aug 2009)
• Questions on BGP AS-Path Filters in Non-Transit Networks (18 Aug 2009)
• What Went Wrong: TCP/IP Lacks a Session Layer (17 Aug 2009)
• Broadband traffic management (10 Aug 2009)
• Blackhat 2009 Router Exploitation presentation (05 Aug 2009)

July 2009

• Aggressive BGP Fall-Over Behavior (29 Jul 2009)
• What is a CTunnel interface? (27 Jul 2009)
• Netflix summary (22 Jul 2009)
• Summer schedule (21 Jul 2009)
• Wimax: the next disruptive technology? (20 Jul 2009)
• Cisco IOS Hints available on Kindle (18 Jul 2009)
• Followup: VLAN interface status (17 Jul 2009)
• PE-to-PE IPSec: do you have creative ideas? (16 Jul 2009)
• Quick tip: VLAN interface status (15 Jul 2009)
• Question everything (13 Jul 2009)
• Looking for additional information on Netflix video streaming (12 Jul 2009)
• Drawing the diagrams (10 Jul 2009)
• Followup: All-I-can-eat (06 Jul 2009)
• What went wrong: end-to-end ATM (03 Jul 2009)
• Not all interfaces are created equal (02 Jul 2009)

June 2009

• ADSL QoS Basics (30 Jun 2009)
• There is no local command authorization (29 Jun 2009)
• Help appreciated: touch-screen drawing (28 Jun 2009)
• IOS HTTP vulnerability (26 Jun 2009)
• Internet anarchy: I’ll advertise whatever I like (25 Jun 2009)
• Autocommands in AAA environment (24 Jun 2009)
• IS-IS Is Not Running over CLNP (23 Jun 2009)
• ADSL Reference Diagram (22 Jun 2009)
• ATM is like a duck (21 Jun 2009)
• Internet Socialism: All-I-can-eat mentality (18 Jun 2009)
• Recommendations for Keepalive/Hello Timers (17 Jun 2009)
• Filter Excessively Prepended BGP Paths (15 Jun 2009)
• GRE Keepalives or EIGRP Hellos? (12 Jun 2009)
• New wireless DOS attacks? … Maybe not. (10 Jun 2009)
• Quick tip: Matching default route in a standard ACL (09 Jun 2009)
• EIGRP Load and Reliability Metrics (08 Jun 2009)
• Multihomed IP Hosts (03 Jun 2009)
• Avoid the prompts generated by the COPY command (02 Jun 2009)

May 2009

• Limitations of VRF Routing Protocols on Cisco IOS (29 May 2009)
• Round-robin NAT: any ideas? (28 May 2009)
• SSH timeouts (26 May 2009)
• How is a device throughput defined (25 May 2009)
• EIGRP Neighbor Loss Detection (22 May 2009)
• Ping priority on Cisco IOS (20 May 2009)
• Another BGP near-miss (19 May 2009)
• BGP basics: BGP communities propagation (18 May 2009)
• Small Site Multihoming Tutorial (15 May 2009)
• IOS Fossils: OSPF-to-BGP Redistribution (13 May 2009)
• Lack of IPv6 Multihoming: the Elephant in the Room? (12 May 2009)
• What does “event none” in an EEM applet mean (11 May 2009)
• Follow my links on Facebook (10 May 2009)
• Blurt from the past: ATM LANE module for Catalyst 3000 (09 May 2009)
• VPLS Is Not Aspirin (06 May 2009)
• Zone-based Traffic Policing (04 May 2009)
• Why Is OSPF (Or IS-IS) Afraid of Unequal-Cost Load Balancing (02 May 2009)

April 2009

• Quick tip: limit SNMP traps sent to a SNMP server (29 Apr 2009)
• OSPF Router ID Selection: the Gory Details (28 Apr 2009)
• SPF Events in OSPF and IS-IS (27 Apr 2009)
• OSPF Router ID Selection Trivia (25 Apr 2009)
• Quick tip: Enable SNMP traps (22 Apr 2009)
• Carrier Ethernet: the big picture (17 Apr 2009)
• Why are there no Untagged entries in my LFIB? (16 Apr 2009)
• True or false: MPLS VPNs offer equivalent security to Frame Relay (15 Apr 2009)
• I hope you knew this already: Backbone-hacking tools (14 Apr 2009)
• IOS interface names (09 Apr 2009)
• Book review: IPv6 Security (08 Apr 2009)
• Traffic Shaping in Cisco IOS (07 Apr 2009)
• Secondary subnets limitation (06 Apr 2009)
• BGP Route Reflector Update Groups (technical details) (02 Apr 2009)
• Another green initiative from Cisco Systems (01 Apr 2009)

March 2009

• Generating layer-2 broadcast from a regular IP packet (30 Mar 2009)
• Ah, the wonderful quoting process (29 Mar 2009)
• Rate-limiting Inbound Traffic on DSL (27 Mar 2009)
• ADSL overhead (26 Mar 2009)
• Line rate and bit rate (25 Mar 2009)
• Bandwidth allocation with class-based weighted fair queuing (CB-WFQ) (24 Mar 2009)
• Over a million page views (21 Mar 2009)
• Blocking rogue DHCP servers (20 Mar 2009)
• Network Migration with BGP Local-AS Feature (18 Mar 2009)
• Off-topic: Search engine wars are over (15 Mar 2009)
• Recovering from expired one-time username (14 Mar 2009)
• EBGP Load Balancing with a Multihop EBGP Session (13 Mar 2009)
• Fat finger follow-up: use the key labels (10 Mar 2009)
• Build a VPN Across Your IP Network with Multi-VRF Feature (09 Mar 2009)
• Are you willing to talk about SP infrastructure optimization? (08 Mar 2009)
• Don't let a lab rat anywhere near a production box (07 Mar 2009)
• Off-topic: Marketing 2.0 (05 Mar 2009)
• Generating syslog messages from Tcl (04 Mar 2009)
• Four byte AS number support in Cisco IOS (03 Mar 2009)
• BGP AS-Path Prepending: Technical Details (02 Mar 2009)
• AS-path incident: the bowdlerizer strikes (01 Mar 2009)

February 2009

• Simulations in certification tests (25 Feb 2009)
• Connecting a switch to itself: does it hurt? (23 Feb 2009)
• Online network diagram drawing tool (21 Feb 2009)
• Oversized AS Paths: Cisco IOS Bug Details (20 Feb 2009)
• Root Cause Analysis: Oversized AS Paths (20 Feb 2009)
• Protect Your Network with BGP maxas-limit (17 Feb 2009)
• Writing good exam questions (12 Feb 2009)
• Yellow journalism at work: Previously Unknown DNS Attacks (11 Feb 2009)
• Off-topic: Workstation vulnerability — FUD at its best (07 Feb 2009)
• Dance around IOS bugs with Tcl and EEM (04 Feb 2009)
• Things you cannot do with Tclsh (03 Feb 2009)

January 2009

• Decent DNS, DHCP and HTTP server on an ISR router (30 Jan 2009)
• The hidden wealth of IOS Tcl (26 Jan 2009)
• I need to slow down :) (24 Jan 2009)
• Interactions between IP routing and QoS (23 Jan 2009)
• Flash-based DHCP database (22 Jan 2009)
• EBGP Multipath Load Sharing and CEF (21 Jan 2009)
• Generate HTTP(S) requests from Tcl shell (19 Jan 2009)
• Can brain dumps be stopped? (14 Jan 2009)
• Extranet with Overlapping Addresses (07 Jan 2009)
• Test the real-life skills of your job candidates (06 Jan 2009)