On Thu, 24 Jan 2008 17:45:58 +0100
Philippe Landau
Messages are again distributed with a delay of about 20 minutes. Is there too much on the server used (lists4.suse.de) ?
There are a lot of reasons for seeing delays from listservs. The first
is that the server itself is bogged down and your emails are delayed
arriving at the server. Usually once emails hit the server, the list
manager turns the email around quickly. The most usual cause of delays
is when the MTA sends the email. Essentially (while there are
efficiencies I am generalizing) each outgoing message is sent to each
respondent's server individually. Usually this requires that the MTA
fork into several processes or threads. There is usually a limit here,
so a number of respondents get placed into the queue. Additionally,
the receiving server must also perform a handshake. There is also a
number of timeouts that also cause some delays. The email's internet
header can give you some indication as to where the delays are.
Looking at the headers for your message, there was a 4 second delay
from your server to mx1.suse.de, then it appears that there was a 4
minute delay internally from mx1.suse.de to relay2.suse.de (where it
scanned the message for viruses). The listserv appears to have turned
the message around in a few seconds, and it took 6 additional minutes
for the MTA at lists4.suse.de to my server. So, on the SuSE side it
appears that relay2.suse.de was a slight bottleneck. Then the message
sat on the MTA's queue for 6 minutes while trying to connect to my
server.
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Jerry Feldman