Re: Postfix SMTP connection cache tagging
- Wietse Venema:
> Looking at Noel's reply to a connection caching question, I realizedThis is not what happens. The SMTP delivery agent prepends its own
> (once again) that the cache is shared among all SMTP clients, even
> across SMTP clients of mail delivery transports.
service name (the first field in master.cf) to the name of every
connection cache entry.
(This is easily verified by setting "scache -v" in master.cf, and
by comparing the logging with "default_transport=smtp" with the
logging of "default_transport=relay").
There is, therefore, no "leakage" of cached sessions from one
transport to another transport, and therefore no "violation" of
sender reputation policies.
> That is a good thing from a connection reuse perspective. It can,
> however, have an unexpected result when different SMTP transports
> have different smtp_bind_address settings. This is done, for example,
> to give different mail streams a different client IP address so that
> their reputations are "separated".
> The way that Postfix currently implements connection reuse, it is
> possible that different mail streams become mixed.
> A possible solution is that an SMTP client tags the connection cache
> with smtp_bind_address information (if non-default) so that it can
> be taken into account when searching the connection cache.