Page 81 - Mercury Manual.book

Outbound SMTP: MercuryC and MercuryE 76
Configuring the MercuryE SMTP client module

if you are having trouble receiving mail from certain sites, but they consume disk space at a
frightening rate. You will typically only use session logging to resolve problems.

DNS timeouts and retries MercuryE is heavily affected by the quality of DNS (Domain
Name Server) services available to it. The process of performing end-to-end SMTP delivery
requires extensive access to the DNS system, and any latency or delay in DNS services can
have a significant impact on the way MercuryE performs. You can adjust the length of time
MercuryE should wait for a DNS response, and the number of retries it will make to get a
response using these controls. Usually, you should use a DNS server that is on the same LAN
backbone as Mercury, but if you are a DNS server that is more remote, you may need to ex-
tend the timeout values here. The default values (20 second timeout with 4 retries) are tuned
to provide a reasonable balance of performance vs reliability when the DNS server is locally
accessible.

Honour requests for transcript generation MercuryE can be asked to produce a transcript of
successful mail deliveries, by adding an "X-Transcript-To: <address>" header to your
messages. When a transcript is requested, MercuryE will send a message containing a tran-
script of the message delivery to the address referenced in the X-Transcript-To header.
While not an absolute proof of delivery, a transcript can provide significant evidence that
your message was actually delivered. If you are using Pegasus Mail, you can use the Custom
headers control in the Special view of the message editor to add an X-Transcript-To head-
er to your mail. Transcript processing introduces a small overhead to message processing, so
if you would prefer MercuryE not to provide transcript processing services, make sure the
Honour requests... control is unchecked. Transcripts are only available (and only meaning-
ful) if you use MercuryE - they are not supported by the MercuryC module.