Re: [exim] Guidance on rate limiting

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Szerző: Ian Eiloart
Dátum:  
Címzett: Graham Butler, 'exim-users@exim.org'
Tárgy: Re: [exim] Guidance on rate limiting


--On 15 January 2009 14:26:54 +0000 Graham Butler <g.butler@???>
wrote:

> Could anybody guide me on the following bit of code for Exim (ver 4.68).
> It is designed as a 'test only' at this stage, until I can get the
> numbers right
>
> Does the ratelimit command updates its stats every time it is called,


IIRC, the answer is "yes", and that's the reason that noupdate was
introduced.

> if so do I need to use the no update options on any subsequent use.


But, I don't think you've used the same key twice, so no you don't need to 
use noupdate. The database keys include the time parameters, and all the 
options, I think:
     10 / 1s / $primary_hostname
     20 / 10m / strict
     1000/ 1h / strict
     100 / 1h / per_rcpt / strict
That's four different rate limits.


To make this more self documenting, you could make explicit the default 
options that you're using, like this:
     10 / 1s / leaky / per_mail / $primary_hostname
     20 / 10m / strict / per_mail / $sender_host_address
     1000/ 1h / strict /per_mail / $sender_host_address
     100 / 1h / per_rcpt / strict / $sender_host_address


It might seem redundant while you're putting this together, but I had to
look these defaults up even though I implemented rate limiting just last
month.

> Any other comments will be gratefully accepted.
>
># ------------------------- Rate limit section ---------------------------
>
># System-wide rate limit 10 per 1 sec (36,000 per hour)
>         warn    ratelimit       = 10 / 1s / $primary_hostname
>                 log_message     = System rate limit exc$sender_rate / 

$sender_rate_period
>
># Rate limit remote servers 20 emails per 10 mins (60 per hour)
>         warn   ratelimit        = 20 / 10m / strict
>                 hosts           = !+relay_from_hosts
>                 senders         = 

!lsearch;/usr/local/exim/tables/ratelimit_whitelist.txt
> log_message     = Remote sender rate limit $sender_rate / 

$sender_rate_period
>
># Rate limiting per local server 1000 per 1 hour (1000 per hour)
>         warn   ratelimit        =  1000/ 1h / strict
>                 hosts           = +relay_from_hosts
>                 senders         = 

!lsearch;/usr/local/exim/tables/ratelimit_whitelist.txt
> log_message     = Local sender rate limit $sender_rate / 

$sender_rate_period
>
># Per user rate limiting 100 per hour (100 per hour)
>         warn    ratelimit       = 100 / 1h / per_rcpt / strict
>                 senders         = 

!lsearch;/usr/local/exim/tables/ratelimit_whitelist.txt
> log_message     =  Per user sender rate limit $sender_rate / 

$sender_rate_period
>
> Many thanks,
>
> Graham Butler
> Email:g.butler@???
>
>
>
>
>
>
>
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--
Ian Eiloart
IT Services, University of Sussex
x3148