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Postscreen and Memcached

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Phil Daws

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Apr 15, 2013, 1:03:11 PM4/15/13
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Hello,

I have postscreen working fine, on localhost, with memcached though am getting confused on how one sets it up for multi-server usage ? We would like out two front-end MTAs to share any IPs that have been added to the cache. How would we achieve this please ?

Many thanks.

Wietse Venema

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Apr 15, 2013, 2:59:29 PM4/15/13
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Phil Daws:
postscreen requires a *persistent* database.

memcached can be used on top of a *persistent* database.

memcached can be shared between between different hosts, but that
is not enough. You need to share the persistent cache, too.

postscreen does not support a *persistent* database that can be
shared between different hosts.

I haven't tried the Postfix memcache client against memcachedb.
This might work, but it may not be fast enough.

Wietse

Stan Hoeppner

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Apr 15, 2013, 10:14:48 PM4/15/13
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Wietse, I recall being part of a discussion quite some time ago, and I
thought this had been worked out already, using proxymap. My
recollection is really vague. What am I remembering, if not postscreen
cache sharing between hosts?

--
Stan

Wietse Venema

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Apr 16, 2013, 7:01:39 AM4/16/13
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Stan Hoeppner:
> Wietse, I recall being part of a discussion quite some time ago, and I
> thought this had been worked out already, using proxymap. My
> recollection is really vague.

Your recollection is incorrect.

> What am I remembering, if not postscreen
> cache sharing between hosts?

This text:

--begin quote--
backup (default: undefined)
An optional Postfix database that provides persistent backup...

# Non-shared postscreen cache.
backup = btree:/var/lib/postfix/postscreen_cache_map

# Shared postscreen cache for processes on the same host.
backup = proxy:btree:/var/lib/postfix/postscreen_cache_map

Access to remote proxymap servers is under development.
--end quote--

Wietse

Stan Hoeppner

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Apr 16, 2013, 7:22:26 PM4/16/13
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I'm not recalling the docs. What I'm vaguely recalling is the
conversation where we discussed methods of implementing the multihost
sharing. IIRC someone mentioned possibly adapting TCP tables for use
here. This was probably part of the same conversation that resulted in
the above feature.

In any event, whatever we discussed hasn't yet been implemented. I
simply had recollection of discussing the multihost feature, but not the
resulting status, which was obviously "future development". Sorry for
wasting time.

--
Stan

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