Blog Posts in 2008

December 2008

Is it wise to use certifications in the candidate selection process? (23 Dec 2008)
MPLS support on 1800-series routers (22 Dec 2008)
Why would I need a Web Application Firewall? (19 Dec 2008)
Book review: Voice over IP Security (12 Dec 2008)
This is QoS; Who Cares about Real-Time Response? (11 Dec 2008)
The most convoluted MIB I’ve seen (10 Dec 2008)
Certifications: a new barrier to entry (09 Dec 2008)
NAT translation logging (08 Dec 2008)
Online session poll results (07 Dec 2008)
Update interval for IOS MIB counters? (06 Dec 2008)
Random “Scenic Route Certification” thoughts (06 Dec 2008)
Should VTP be disabled by default? (04 Dec 2008)
I’m Too Old … I Prefer CLI over GUI (02 Dec 2008)
When Would an MPLS LSR Have Untagged Output Label? (01 Dec 2008)

November 2008

Sometimes the path is more important than the destination ... (28 Nov 2008)
This is why I don’t trust “independent experts” (27 Nov 2008)
Stuffing the polls: the adventures of a convoluted mind (25 Nov 2008)
An offer you should not refuse (24 Nov 2008)
Online sessions in December 2008: please vote! (24 Nov 2008)
How should I cover ACE XML Gateway and Web Application Firewall? (23 Nov 2008)
Annotate your router sessions (22 Nov 2008)
3 reasons why I would like to have DNS lookups in IOS access lists (21 Nov 2008)
Using hostnames in IP access lists (19 Nov 2008)
The best way to learn: solve a hard challenge (18 Nov 2008)
MPLS QoS: Implementing the best model for guaranteed service (17 Nov 2008)
Interactive online sessions: your input is highly appreciated (14 Nov 2008)
ACL object groups (13 Nov 2008)
Control Plane Protection Overview (12 Nov 2008)
Becoming a spammer: hands-on experience (11 Nov 2008)
Book review: Cisco Secure Firewall Services Module (10 Nov 2008)
Off-topic: disappointed by the antivirus industry (09 Nov 2008)
Interesting links | 2008-11-08 (08 Nov 2008)
Bidirectional Forwarding Detection (07 Nov 2008)
Mixing Numbered and Unnumbered OSPF Interfaces: Solution (04 Nov 2008)
Was it really only a century ago? (01 Nov 2008)

October 2008

OSPF Challenge: Mixing Numbered and Unnumbered Interfaces (29 Oct 2008)
OSPF LAN Adjacency Challenge: Final Results (29 Oct 2008)
Who is an associate? (28 Oct 2008)
Telnet access restrictions (24 Oct 2008)
IP address lookup (22 Oct 2008)
Gaining Knowledge - what’s the best way to do it? (20 Oct 2008)
Challenge: Establish OSPF Adjacency on a LAN Interface (18 Oct 2008)
OSPF Breaks When Faced With Overlapping IP Addresses (17 Oct 2008)
OSPF Ignores Subnet Mask Mismatch on Point-to-Point Links (16 Oct 2008)
Troubleshooting OSPF Adjacencies (15 Oct 2008)
Quality in training: you can make a difference (14 Oct 2008)
Display Interfaces Belonging to a Single OSPF Process (13 Oct 2008)
MPLS on 7600: the devil is in the details (11 Oct 2008)
IP QoS: Two generations of class-of-service tools (10 Oct 2008)
AAA command authorization gotchas (09 Oct 2008)
Specify MPLS TE bandwidth as percentage of interface bandwidth (08 Oct 2008)
Leak Map Confusion (07 Oct 2008)
Internet Access Russian Dolls (05 Oct 2008)
RIP Rocks in Low-End Hub-and-Spoke Networks (01 Oct 2008)

September 2008

Why is RIP still kicking? (30 Sep 2008)
Enhance the Traceroute Output (29 Sep 2008)
Multilink bundles have varying bandwidth (25 Sep 2008)
Do you need LDP with MPLS TE? (24 Sep 2008)
Load balancing quirks (23 Sep 2008)
Knowledge or recipes? (21 Sep 2008)
Interesting links | 2008-09-21 (21 Sep 2008)
Quick tip: display interface bandwidth (19 Sep 2008)
PE-to-PE Troubleshooting in MPLS VPN Networks (18 Sep 2008)
MPLS Essentials: Implicit and explicit NULL (17 Sep 2008)
Interesting links | 2008-09-14 (14 Sep 2008)
Quick tip: display interface IP addresses (12 Sep 2008)
Default Routing in NSSA Area (10 Sep 2008)
Are VLANs safe in DMZ environment? (09 Sep 2008)
End-to-End Responsibility (06 Sep 2008)
Some DHCP clients do not use Client identifier option (03 Sep 2008)
BGP route aggregation: followup (02 Sep 2008)
Practical BGP-based hijack/man-in-the-middle attack (01 Sep 2008)
Send e-mail after a router reload (01 Sep 2008)

August 2008

Small enhancement in zone-based firewalls (31 Aug 2008)
Load Balancing with Parallel EBGP Sessions (29 Aug 2008)
SNMP v3 users not shown in running-config (28 Aug 2008)
IOS scheduling parameters (27 Aug 2008)
RIP route database (26 Aug 2008)
Do you have a good reason to use BGP aggregation? (25 Aug 2008)
Is a label imposed in case of Penultimate Hop Popping? (21 Aug 2008)
Reverse Lookup of OSPF Router IDs (20 Aug 2008)
Measure the cable lengths on a Catalyst switch (16 Aug 2008)
DNS view-groups don't work on subinterfaces (15 Aug 2008)
CCIE is devalued? Get real. (14 Aug 2008)
Primary/Backup Area Border Router Designs (13 Aug 2008)
Make the "show" command available in configuration mode (11 Aug 2008)
Interesting links | 2008-08-10 (10 Aug 2008)
BGP Route Reflector Details (08 Aug 2008)
SSH works without AAA (07 Aug 2008)
Related posts in IOS hints blog (07 Aug 2008)
Identifying TACACS+ failure (04 Aug 2008)
OSPF in a VRF Requires a Box-Unique Router ID (01 Aug 2008)

July 2008

Interesting links | 2008-07-27 (27 Jul 2008)
Router configuration partitioning (23 Jul 2008)
Unequal-Bandwidth EBGP Load Balancing (21 Jul 2008)
Goodbye fast switching & cell-mode MPLS (18 Jul 2008)
Interesting links | 2008-07-13 (13 Jul 2008)
How obscure can it get?: BGP IPv6 printouts (11 Jul 2008)
Global IPv6 strategies (10 Jul 2008)
QoS Policing in Cisco IOS (09 Jul 2008)
The Value of Being a CCIE (08 Jul 2008)
Wonderful Cisco IOS documentation (07 Jul 2008)
Simple CLI extensions: handling special characters (07 Jul 2008)
What Is Anycast? (03 Jul 2008)
Multihomed EIGRP Sites in MPLS VPN Network (02 Jul 2008)
Why I'm no longer an active CCIE (01 Jul 2008)

June 2008

DNS views work with EEM (30 Jun 2008)
Simple extensions to exec-mode CLI (30 Jun 2008)
Is Internet Melting Down? (29 Jun 2008)
Using EIGRP in MPLS VPN Networks (26 Jun 2008)
Static DHCP assignment for clients without client-id (25 Jun 2008)
PPP default route (24 Jun 2008)
Display locally originated BGP routes (18 Jun 2008)
Control Plane Protection logging does not work on transit subinterface (17 Jun 2008)
IOS auto-upgrade (16 Jun 2008)
Web 2.0 presentation (15 Jun 2008)
Display BGP routes originated in the local AS (10 Jun 2008)
Fix the "do" command (09 Jun 2008)
Configuring lines and terminals (07 Jun 2008)
Use the explicit "address-family ipv4" in BGP configurations (05 Jun 2008)
CEF and MLS (04 Jun 2008)
Another Way to Generate SNMP Trap on High CPU Load (03 Jun 2008)
Programming language consistency (02 Jun 2008)
Generate SNMP trap on high CPU load (02 Jun 2008)

May 2008

Much ado about rootkits (31 May 2008)
Display CPU utilization with every show command (29 May 2008)
Conditional BGP Route Origination (28 May 2008)
Continuous display of top CPU processes (26 May 2008)
Router architecture books (24 May 2008)
Cable modem problems with Cisco 871 (21 May 2008)
Multihoming to a Single ISP (20 May 2008)
Guide to Harden Cisco IOS Devices (18 May 2008)
Using IP Prefixes, AS Numbers and Domain Names in Examples (17 May 2008)
Control Plane Protection inbound packet classification (15 May 2008)
Which routing protocol do you use? (14 May 2008)
Cisco 851 and 871 bridge between LAN and WAN interfaces during boot process (13 May 2008)
RTBH links (and thanks for the acronym :) (12 May 2008)
How do you know you're an SP-geek (11 May 2008)
Please Comment: Is Asymmetric Routing Harmful? (10 May 2008)
The “fallback global” VRF option does not exist in Cisco IOS (07 May 2008)
A bug in the IOS “section” filter (06 May 2008)
Web Citation Archive (05 May 2008)
Labor day (01 May 2008)

April 2008

The Impact of tx-ring-limit (30 Apr 2008)
Display operational IPv6 interfaces (29 Apr 2008)
What Is CLNS? (27 Apr 2008)
MAC addresses on VLAN interfaces (26 Apr 2008)
Almost-Dynamic Routing over ADSL Interfaces (23 Apr 2008)
Hot air party (20 Apr 2008)
Interesting posts (19 Apr 2008)
OSPFv3 Router ID: the Long Shadow of IPv4 (17 Apr 2008)
Subnet Masks in OSPF Network Statements (15 Apr 2008)
Technology Is Supposed to Be Simple, Right? (10 Apr 2008)
BGP Essentials: Non-transit AS (08 Apr 2008)
Use UDP flood to increase router's CPU load (03 Apr 2008)
Do bootcamps make sense? (02 Apr 2008)
RFC 3514 implemented by the ASR series of routers (01 Apr 2008)

March 2008

Tcl-based IOS backdoor (31 Mar 2008)
Track the DHCP Default Route (29 Mar 2008)
NAT activates NBAR (26 Mar 2008)
Detect routers operating in process-switching mode (25 Mar 2008)
Predefine your own Tcl functions (24 Mar 2008)
Local-AS Has to Be Matched by Incoming Filter-List (20 Mar 2008)
When “copy” actually means “merge” (19 Mar 2008)
SNTP will not work if you've configured NTP (18 Mar 2008)
Use EEM to respond to ERM events (17 Mar 2008)
How Do I Detect Router Restarts? (15 Mar 2008)
The Mysteries of the “Internet” BGP Community (13 Mar 2008)
Detect CPU spikes with Embedded Resource Manager (12 Mar 2008)
Display the names of the configured route-maps (10 Mar 2008)
Copy file to an FTP server with EEM applet (08 Mar 2008)
Use extended access-lists to filter BGP updates (06 Mar 2008)
Router Fragmentation Is Gone from IPv6 (05 Mar 2008)
WAN IP addresses and subnet masks (04 Mar 2008)
Phase 2: Upload text files through a Telnet session (03 Mar 2008)
Debugging time-based configuration (02 Mar 2008)

February 2008

Building Customer-Resilient BGP networks (29 Feb 2008)
Unconditional trunking port on a Catalyst 3560 (28 Feb 2008)
Merging VTY configurations (27 Feb 2008)
Reduce IP addressing errors in lab environment (26 Feb 2008)
Time-based BGP policy routing (25 Feb 2008)
Environment variables set by EEM applet action commands (24 Feb 2008)
“Cisco IOS Hints” blog featured in NetworkWorld (21 Feb 2008)
Use all the tools you have (21 Feb 2008)
Differentiating between port scanners and legitimate users (20 Feb 2008)
Remove unwanted PPP peer route (19 Feb 2008)
Implement “wc -l” in Cisco IOS (18 Feb 2008)
Common Sense Prevails Over RFC 2328 (14 Feb 2008)
AS-path Based Filter of Customer BGP Routes (13 Feb 2008)
Configure OSPF on Unnumbered Interfaces (12 Feb 2008)
Fix bugs in EEM action cli implementation (11 Feb 2008)
BGP Essentials: AS-path Prepending (07 Feb 2008)
Interesting QoS problem on Catalyst 3750 (06 Feb 2008)
Use Slow IGP Startup in LDP-only MPLS Environments (05 Feb 2008)
BGP Essentials: BGP Communities (04 Feb 2008)

January 2008

TCAM on Catalyst switches (31 Jan 2008)
Redistributing Customer Routes into BGP (30 Jan 2008)
BGP Peer Session and Policy Templates (29 Jan 2008)
Telnet/SSH session cannot be started from EEM applet (28 Jan 2008)
The short story of the “ip default-network” command (27 Jan 2008)
Hyperlinked RFCs (26 Jan 2008)
OSPF Default Route Based on IP SLA (24 Jan 2008)
Advertising Public IP Prefixes into the Internet (23 Jan 2008)
Configuring Internal BGP Sessions (22 Jan 2008)
The history of Cisco CLI (21 Jan 2008)
Restart IOS DHCP server after a change in DHCP pools (16 Jan 2008)
Setup DNS server in your lab (15 Jan 2008)
Copy the text files into router's flash through a Telnet session (13 Jan 2008)
WAN emulation toolkit (12 Jan 2008)
The Never-Ending Story of IP Fragmentation (11 Jan 2008)
DHCP Conflict between a Cisco Router and Windows DHCP Server (10 Jan 2008)
Fix a BGP AS Number Mismatch (09 Jan 2008)
Simplify your lab work (08 Jan 2008)
Configure the default route based on the presence of a BGP session (07 Jan 2008)
Define new IOS commands with the alias functionality (01 Jan 2008)