Google Message Security for Google Apps Administration Guide - Manual (Page 402)

402 Message Security for Google Apps Administration Guide
To open the full header in Google Apps:
1. Log in to Gmail.
2. Open the message whose header you want to see.
3. Click the down arrow next to Reply, at the top-right of the message pane.
4. Select Show original. The full header appears in a new window.
Received Header Field
The service includes a “Received” header field in each message processed. This
information includes the IP address of the sender, any details on TLS (Transaction
Layer Security, an optional feature) secure transmission from the sending server,
the particular server that processed the message, the digital signature that is
added to let the system distinguish between legitimate NDRs for your messages
and NDRs that result from spammers using forged addresses, and a timestamp.
An email message that passed through the message service will have header
fields similar to the following:
Received: from source ([172.18.76.29]) by exprod8ob108.postini.com
([64.18.7.12]) with SMTP
ID [email protected]; Thu, 14
Aug 2008 00:11:18 PDT
If you don’t see a header field with the domain similar to exprodNmxM.postini.com
(for example, exprod8mx8.postini.com ), the message did not go through the
message service, and was delivered directly to the recipient’s server.
TLS delivery from the sending server to the message security service is indicated
by “
using TLSv1 ” or “ using SSLv3 ”, for example:
Received: from source ([12.158.40.254]) (using TLSv1) by
exprodNmxM.postini.com; Wed, 08 Jan 2007 14:39:55 PST
Received: from source ([12.158.40.254]) (using SSLv3) by
exprodNmxM.postini.com; Wed, 08 Jan 2007 15:02:31 PST
(Your mail server may add similar details to the header to indicate that the
message was received via TLS from the message security service.)
The digital signature takes a form like the following:
ID [email protected];
The digital signature is added to support the Null Sender Disposition spam filter.
X-pstn-levels Header Field
The letter/number pairs that appear on X-pstn-levels tell you which filters (if any)
were triggered and to what degree. The letters that may appear on this line are: