Ivan Pepelnjak
Two days ago I’ve managed to write aGenuineStupidity™ (OK, maybe I cannot get a trademark on this concept): the MQC shaping actions cannot be attached to a Dialer interface; they have to be specified on the underlying physical interface (in case of PPPoE link, the outside Ethernet...
Ivan Pepelnjak
Red Pineapple was kind enough to share his 15-year-old ATM slides...
Ivan Pepelnjak
Last week I happened to be copied on an e-mail which included a PDF describing a “SP Services and Solutions” bootcamp I knew nothing about...
Ivan Pepelnjak
Based on the ADSL reference model we’ve discussed last week, let’s try to figure out how you can influence the quality of service over your ADSL link (for example, you’d like to prioritize VoIP packets over web download)...
Ivan Pepelnjak
Shahid wrote me an e-mail asking about local command authorization...
Ivan Pepelnjak

Ivan Pepelnjak If you're old enough to remember Thick Coax Ethernet with the vampire taps, pleasant memories will probably surface after reading this article.

Source: www.potaroo.net
As I write this, on the 23rd June 2009, I've been reminded that some 20 years ago, on the night of the 23rd June 1989, Robert Elz of the University of Melbourne and Torben Neilsen of the University of ...
Ivan Pepelnjak
I’m looking for a touch screen device that would work (well) with PowerPoint. I’d like to start drawing my diagrams with a pen, not with a mouse; I have a completely unfounded irrational belief that drawing with a pen might be faster and easier than using a mouse. Any (tested) ideas?
Ivan Pepelnjak

Ivan Pepelnjak Four pretty serious potentially exploitable Facebook privacy issues

Source: theharmonyguy.com
For the record, Facebook has some of the most flexible and robust privacy controls I’ve seen in any online social networking service. I never want to take for granted that Facebook engineers have ...
Ivan Pepelnjak

Ivan Pepelnjak A nice overview of the IPv6 address space

Source: www.potaroo.net
If you have enabled IPv6 on your computer, and in an idle moment you've browsed through the interface configuration information for IPv6 addresses you may have been a little surprised by the fact that there's not just one IPv6 address that's been loaded, but many. ...
Perron
Perron
so many addresses even your toaster can be on the Internet. Talk about big brother!
Ivan Pepelnjak
The Cisco Subnet RSS feed I’m receiving from Network World contained interesting information a few days ago: Cisco has reissued the HTTP security advisory from 2005...
Ivan Pepelnjak

Ivan Pepelnjak Interesting argument: you lose if you act on misbehavior of your customers, you lose if you don't.

Source: www.cisco.com
There is a long-standing role in the communications industry where a provider of public carriage services undertakes the role of a common carrier. What's so special about the role of a common carrier, ...
Ivan Pepelnjak
We all know that the global BGP table is exploding (see the Active BGP entries graph) and that it will eventually reach a point where the router manufacturers will not be able to cope with it via constant memory/ASIC upgrades (Note: a layer-3 switch is just a fancy marketing name for a router)...
Ivan Pepelnjak
A reader who prefers to remain anonymous has reported an interesting observation: autocommands configured on local usernames do not work after configuring aaa new-model.This article is part of You've asked for it series. Read more in Cisco IOS Hints and Tricks blog
Ivan Pepelnjak
A while ago I’ve received an interesting question from someone studying for the CCNP certification: “I know it’s not necessary to configure clns routing if I’m running IS-IS for IP only, but isn’t IS-IS running over CLNS?”I’ve always “known” that IS-IS uses a separate layer-3...
Ivan Pepelnjak
I’m getting lots of ADSL QoS questions lately, so it’s obviously time to cover this topic...
Ivan Pepelnjak
It was (around) 1995, everyone was talking about ATM, but very few people knew what they were talking about...
Ivan Pepelnjak
Swapnendu was trying to implement inter-VRF route leaking in multi-VRF environment without using route targets...
Perron
Perron
interesting.
Ivan Pepelnjak

Ivan Pepelnjak Brad Reese stumbled on a gold nugget. Excellent text by George Morton.

Source: www.networkworld.com
18Mbps down and 2Mbps up service for 15% of the cost of T1 service, 36Mbps down and 4Mbps up service for 33% of the cost of T1 service
Ivan Pepelnjak

Ivan Pepelnjak I like the quote at the end of the article: "My competitors are welcome to them. They won't earn anything on them either."

Source: www.telegeography.com
Dutch telecoms operator KPN says it will stop offering free mobile handsets to customers taking out a pay-as-you-go package
Stevko Trajkovski

Stevko Trajkovski hi Ivan,
Do you have any cisco configuration for "Dual Internet Connections without BGP enabled ISP" which really works?
note: all configuratios i tested on cisco1841 have some bugs

THX :)

Ivan Pepelnjak
Ivan Pepelnjak
The configurations I've published in the "Small site multihoming" series were all tested (I would never publish a Notepad-generated configuration), but maybe not thoroughly enough.

Get in touch with me with specific issues and we'll try to figure something out.
Ivan Pepelnjak
The “GRE keepalives or EIGRP hellos” discussion has triggered another interesting question:Is there a good rule-of-thumb for setting hold-down timers in respect to the bandwidth/delay of a given link...
Ivan Pepelnjak

Ivan Pepelnjak Paul McNarama could easily use the same approach on NetworkWorld articles ;)

Source: www.networkworld.com
... or, 'How headline writers create news.'
Ivan Pepelnjak
A few months ago, a small ISP was able to disrupt numerous BGP sessions in the Internet core by prepending over 250 copies of its AS number to the outbound BGP updates...
Calin
Calin
Why in the name of God they would choose to prepend 250 copies?!
Ivan Pepelnjak
Ivan Pepelnjak
Read the linked-to posts :) They've used a weird box that has IOS-like CLI but expects the number of AS numbers to prepend, not the actual AS path (and fails to check the parameters :D ).
Ivan Pepelnjak

Ivan Pepelnjak Great interview with Randy Bush. Very interesting thoughts about costs experienced when hitting the IPv4 wall (starting @ 02:30).

Source: www.youtube.com
Ivan Pepelnjak

Ivan Pepelnjak Interesting social engineering tactics

Source: www.informit.com
If someone you trusted has ever tricked you, you know what it feels like to be socially engineered. Security expert Andrew Whitaker explains both the technical and non-technical techniques used by social engineers today to gain trust and manipulate people for their benefit. ...
Yasser
Yasser
Good :)
Ivan Pepelnjak
It looks like everyone who’s not using DMVPN is running IPSec over GRE these days, resulting in interesting questions like »should IP use EIGRP hellos or GRE keepalives to detect path loss?«Any dedicated link/path loss detection protocol should be preferred over tweaking routing protocol timers...
Ivan Pepelnjak
I had an interesting debate with an engineer who wanted to use TFTP between a router and a server reachable through an outside interface...
Ivan Pepelnjak

Ivan Pepelnjak Involved in project or team management?

Source: www.alistapart.com
If I move a muscle, I’m dead. Jane, who I’m pretty sure is a Werewolf, is jumping from one player to the next, testing will and looking for weakness. She’s looking for a sign of guilt or discomfort and it’s not just her. ...
Ivan Pepelnjak
A few days ago, City College of New York hosted the “Cyber Infrastructure Protection Conference”, including a keynote speech by Krishnan Sabnani who described “new class of denial-of-service (DOS) attacks that threaten wireless data networks” … or so the Network World claims in its...
Ivan Pepelnjak

Ivan Pepelnjak Don't guess. Test. Works every time (even in web design).

Source: www.useit.com
Even the tiniest amount of empirical facts (say, observing 2 users) vastly improves the probability of making correct UI design decisions.
Ivan Pepelnjak
I've got the following question from Matthew: »how would one go about matching the default route for filtering using standard ACLs?«In all routing protocols but EIGRP (which can carry the »default candidate« flag on any IP prefix), the default route has IP address 0.0.0.0 and subnet mask...
Ivan Pepelnjak

Ivan Pepelnjak T-mobile hit by hackers?

Source: www.networkworld.com
T-mobile customers are awakening this morning to reports that hacker/extortionists have victimized the cellular carrier through a massive network breach resulting in the theft of untold amounts of corporate and customer data, which they're threatening to sell to the highest bidder.
Ivan Pepelnjak
Everyone studying the EIGRP details knows the “famous” composite metric formula, but the recommendation to keep the K values intact (or at least leaving K2 and K5 at zero) or the inability of EIGRP to adapt to changing load conditions is rarely understood.IGRP, the EIGRP’s predecessor, had...
Ivan Pepelnjak

Ivan Pepelnjak It's too late for true dual stacking

Source: www.networkworld.com
We are entering the transitional period between IPv4 andIPv6, and things are going to get awkward for a while. IPv4 addresses will officially be used up in the next couple of years, although for most practical purposes you can consider the pool of unallocated IPv4 addresses to be depleted already. ....
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Ivan Pepelnjak commented on their own note Filter excessively prepended BGP paths.