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    • Favorite 13 March 2019
      bobjonkman favorited something by lnxw48a1: You go to post, you look it over. It looks okay. Hit "Post" and now there are words missing, words spelled incorrectly, punctuation missing.
    • bobjonkman repeated a notice by lnxw48a1 13 March 2019
      RT @lnxw48a1 You go to post, you look it over. It looks okay. Hit "Post" and now there are words missing, words spelled incorrectly, punctuation missing.
    • New note by bobjonkman 7 March 2019
      If you have an external clock that's transmitted exclusively over an analogue channel, then everyone would hear the beats at the same time (barring speed-of-light transmission times, which is really only a factor if the transmission uses geosynchronous satellites). But if there is any digital transmission then you're back to the same problem. Not everyone […]
    • bobjonkman repeated a notice by lauraritchie 7 March 2019
      RT @lauraritchie @bobjonkman @strangeattractor what if they instead of playing reactively everyone played to a world clock? - people could always record their contributions and video magic can be done with screens in a room and then the one room is streamed.
    • New note by bobjonkman 4 March 2019
      The solution would be to have an analogue connection from end-to-end. But today, even analogue phones are connected to digital switching networks, so you can't even use ordinary landline phones and expect to get no delay. You can get "leased lines" from the phone companies that are analogue end-to-end, but leasing a tuned circuit that […]
    • New note by bobjonkman 4 March 2019
      Performing music together over an Internet connection is next to impossible if there is *any* lag at all. Typically, the lag is caused by short 10-50 millisecond delays for every router hop, at minimum one hop from you to your ISP, another from ISP to Internet Exchange Point (IXP), IXP to my ISP, and a […]
    • bobjonkman repeated a notice by lauraritchie 4 March 2019
      RT @lauraritchie More on the livestreaming dilemma...I need to have the option of multiple participants AT THE SAME TIME - like playing in a band. So maybe the keyboard and drums are in one place (live) and the sax player joins from another country via a link. Does anyone know of a platform that lets […]
    • New note by bobjonkman 3 March 2019
      The duct tape is in very good condition.
    • New note by bobjonkman 3 March 2019
      Test receive, also pls ignore
    • New note by bobjonkman 25 February 2019
      ...and wouldn't you have to include the time to insert 225,000 microSD cards in your laptop, write 256 GBytes to them, and then (after transporting them at about 10 PBytes/second, assuming 6 seconds of flight time), spend more time to insert those 225,000 microSD cards in the other guy's laptop to read those 256 GBytes? […]

Archive for November, 2009

Blacklists considered harmful

Posted by Bob Jonkman on 19th November 2009

The black hole that sucks up Internet Addresses

The black hole that sucks up Internet Addresses

BoingBoing points me to a Security Fix article by Brian Krebs called A year later: A look back at McColo on the after-effects of Real-time Blacklists (RBLs) that targeted formerly undesirable IP addresses:

The Internet community typically shuns networks known to harbor spammers and organizations that host malicious software and other nastiness, usually by including their numeric Internet addresses on “blocklists”. Many organizations configure their e-mail servers to reject messages from addresses included on one or more of these blocklists. A heavily blocklisted network quickly becomes unattractive to legitimate businesses, since any e-mail sent out of that network will most likely be refused by the intended recipients.

“The problem is once an address block gets so polluted and absorbed into all these blocklists, it’s difficult to get off all of them because there is no central blocking authority,” said Paul Ferguson, an advanced threat researcher at Trend Micro.

(“Blocklist” is a less pejorative term for “Blacklist”)

The problem is not with the (formerly) malicious site, nor with the keepers of the blacklists, or even the lack of a central blocking authority. The problem is with e-mail server admins or firewall admins who let some unpaid, unaccountable blacklist censor their incoming mail or access to Web pages.

A blacklist should be just one of the criteria used to weight the probability that an incoming e-mail message is spam, or that an http stream contains malware. When I use a blacklist I’ll take into account the blacklist’s opinion of an IP source, but I don’t want a blacklist deciding what I can or can’t receive.

It’s far more reliable to actually examine the content stream for spam or malware instead of relying on a third-party’s opinion of an IP address. Yes, this increases the transaction cost for managing spam and malware, but as these blacklist IP address areas increase there’s an ever greater chance of false positives.

Are you using blacklists? Still think they’re a good idea? Wait until your blacklist gets compromised. An attacker takes control of a blacklist, but doesn’t interfere with its regular operations. Instead, it selectively adds and removes addresses. What better way to impose a DoS attack than maliciously subscribing your target to a well-known blacklist? In fact, for the long con I can see an attacker setting up a blacklist site, and spending a year or two building a reputation. As long as system admins rely completely on that blacklist to block certain IP addresses, those system admins are vulnerable to the whims of the blacklist operator.

I also wrote about the role of blacklists in Blocking Port 25 Considered Harmful, just under a year ago.

–Bob.

(Flickr image “Black Hole” by he who shall used under creative commons license)

Posted in considered harmful, dnsbl | Comments Off on Blacklists considered harmful

Deep Packet Inspection considered harmful

Posted by Bob Jonkman on 13th November 2009

Ripe for Deep Packet Inspection

Ripe for Deep Packet Inspection

Michael Geist points us to a Sandvine report analyzing global broadband traffic.

Far more interesting than the data presented by Sandvine is the fact that Sandvine has any data to present at all. How did they get this stuff? Did they buy it from Bell and Rogers? Does their throttling equipment phone home? I don’t recall giving them permission to use my data.

They claim they’re not looking at data content. Maybe that’s true, maybe it’s not. But they’ve inspected deeply enough to know that we use more streaming applications than P2P, and more Bittorrent than Gnutella. As any data analyst knows, traffic analysis of data patterns gives as much information as the data itself. Why are they allowed to gather any of this data at all? None of their business what I use on my computer.

I’m sure Sandvine is making a hefty buck selling this report, or at least using it as evidence to sell more of their DPI equipment. They’re profiting from the the data that I didn’t give them permission to use. I think the Privacy Commissioner may want to look into this.

–Bob.

Posted in considered harmful, Deep Packet Inspection, privacy | Comments Off on Deep Packet Inspection considered harmful

 
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