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Davesnothere
No-BHELL-ity DOES have its Advantages
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join:2009-06-15
START Today!
kudos:7

1 edit
reply to gweidenh

Re: CC Disaster

said by gweidenh:

I do not know exactly when. I checked this morning based on Iscream's response about changing their DNS SRV weighting.

I am talking specifically about the srv.callcentric.com records.

 
Yes, I too noticed that change at that same period, and was meaning to ask wassup - now has less servers in the response for srv.callcentric.com - though I had not suffered registration problems yesTURDay.

Also, all of the weights on that are set to 30 now.

At that time, the 'A' record (callcentric.com) reply was still longer and all weights still at ZERO.

EDIT : Actually, it was shorter than it USED to be, but longer than the reply for SRV.

SRV now shows 9 servers, and 'A' shows a total of 11 today.

Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
Reviews:
·Verizon FiOS

Dave - "A" records don't have "weights", they have only IP addresses; that's a whole "problem" with them. On another hand - "SRV" records don't have IP addresses, but they resolve to different names (where each name may have multiple IP addresses), different priorities and different weights. This [SRV] mechanism allows for redundancy (including so beloved here - geo-redundancy) on multiple levels, it allows a granular prioritization of serving components (servers) including further prioritization within a group of equal servers - this is controlled by weights.

The result is an ability to protect from DoS and DDOS attacks by creating a huge capacity of fast moving targets changing their parameters quickly in "invisibly" for attackers by replacing actual serving, but currently [over]loaded computers, in real time, within milliseconds, with fresh and not loaded ones while allowing the former keep processing earlier started requests and dialogs.

Also the result is an ability to have a self-healing farm of servers where any server may go south (die) at any moment without affecting any devices working with that farm. The farm may have servers co-located within same room or groups of servers spread geographically (provided all distributed servers have equal resources Internet-wise - same sufficient bandwidth, same speed and same access to originating and terminating carriers which is not the easiest and rather literally and largely impossible part for most today's providers - this is why I'm so against geo-redundancy, but I'll stop on that again later).



Davesnothere
No-BHELL-ity DOES have its Advantages
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join:2009-06-15
START Today!
kudos:7

3 edits

1 recommendation

said by Iscream:

....The result is an ability to protect from DoS and DDOS attacks by creating a huge capacity of fast moving targets, changing their parameters quickly in "invisibly" for attackers by replacing actual serving, but currently [over]loaded computers, in real time, within milliseconds, with fresh and not loaded ones while allowing the former keep processing earlier started requests and dialogs....

 
I see.

This reminds me of that old arcade game at county fairs where you shoot at the ducks and knock them down.

However, there always seem to be more ducks to replace them - maybe even the SAME ducks - but we cannot see what happens below the deck, and it really does not matter, as long as more ducks come into the sight of the rifle.

EDIT : Please note that in this example, WE play the part of the attackers, and no matter how many ducks we knock down, there always seem to be more.

Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
Reviews:
·Verizon FiOS

I'd say - it reminds a game/screen-saver/trojan-virus where an entire screen surface quickly populates with cockroaches getting from anywhere where you're required to knock them down by either mouse or fingernail, but they keep coming in, more and more... until you use something like DDT or just remove the software that irritates your mind )


OmagicQ
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join:2003-10-23
Bakersfield, CA
kudos:1
Reviews:
·Bright House

1 recommendation

reply to Iscream

said by Iscream:

... The farm may have servers co-located within same room or groups of servers spread geographically (provided all distributed servers have equal resources Internet-wise - same sufficient bandwidth, same speed and same access to originating and terminating carriers which is not the easiest and rather literally and largely impossible part for most today's providers - this is why I'm so against geo-redundancy, but I'll stop on that again later).

Really...How very interesting....
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...Who, What, When, Where, How... Why? Why Not?