DCC server high latency

Mark v Herpen markvh@office.cambrium.nl
Fri Jan 25 10:21:51 UTC 2008

Vernon Schryver wrote:
>> From: Mark v Herpen <markvh@office.cambrium.nl>
>> To: dcc@rhyolite.com
>> I've installed the dcc daemon, but the latency to this server on 
>> localhost is higher than the latency to the public servers.
>> When I do a cdcc info on the same machine as where the dcc daemon runs, 
>> I get '400 ms queue wait' as response.
>> I think it is typical that it alway exact 400 ms, so perhaps I forgot a 
>> some configuration option.
>> The version of DCC is 1.3.80 and it doesn't matter if i connect to 
>> or the public IP address.
>> Can someone give me some advice?
> DCC stands for "distributed checksum clearinghouses."   The basic
> idea is to pool information about incoming mail with clearinghouses
> to recognize bulk mail.  That idea makes no sense unless that
> information is from more than one mail system.
> Each sane DCC server exchanges or "floods" information with 3-4 peers.
> If network problems or maintenance disconnect a DCC server from all of
> its peers, it artificially delays its responses to encourage its DCC
> clients to switch automatically to another DCC server.
> Please note that running DCC servers not connected to the global
> network of DCC servers violates the license on the code.  By running
> a private DCC server that is not exchanging checksums with other
> DCC servers or "flooding," you are violating this paragraph of the
> license on the free version of the code that is in all of the files:
>  * This agreement is not applicable to any entity which sells anti-spam
>  * solutions to others or provides an anti-spam solution as part of a
>  * security solution sold to other entities, or to a private network
>                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> You need to buy a license for the commercial version of the code
> to run a private network of DCC servers.  I think there are good
> reasons for some organizations to buy the commercial code, but I
> doubt it makes sense to run a private, disconnected DCC network
> even with the commercial code.
> That restriction in the license exists only to add a handle on
> certain appliance and filter service vendors that do not qualify
> for the free version of the DCC code but that use it regardless.


The thing is that I wanted to test the DCC server, before I wanted to 
connect it the the global network of DCC servers. Because the latency 
was so high, I wanted to fix this first, before contacting you for a 
server ID or the contact other persons the exchange checksums.

I didn't see the 'artificially delaying of the DCC server when its 
disconnected to other peers' in the documentation. So I was thinking 
that I did something wrong. Perhaps it's is a good thing to include this 
in the DCC docs. :)

I will contact you personal for a server-id and other info.


Mark van Herpen

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