Kevin_Miller at ci.juneau.ak.us
Fri Jul 15 20:52:32 IST 2011
I've enabled watermarking on my MailScanner boxes. I'm stil in the testing phase so MS evaluates watermarks but does nothing with them yet.
On my outbound host I see a number of entries of in maillog similar to:
"Message p6EJliaG019866 from 220.127.116.11 has no (or invalid) watermark or sender address : 1 Time(s)"
These are from my Exchange server, which doesn't know anything about watermarking but points to my egress host. Probably nothing to do about them but since all traffic is outbound I guess they can be safely ignored. I can probably 'fix' those on the outbound server by either changing "Check Watermarks To Skip Spam Checks yes" to "no", or changing "Check Watermarks With No Sender" to a ruleset that excludes my Exchange server, right?
Inbound traffic is a bit different though. On my inbound gateways I'll see messages in /var/log/mail such as:
"Jul 14 14:29:56 mxg MailScanner: Message p6EMTjEK006009 from 18.104.22.168 has no (or invalid) watermark or sender address"
which aren't NDRs, but out of office messages. They come in without an envelope sender and, of course, no watermark since they're not from one of my servers.
How are folks dealing with them? They're not spam, so marking them as such isn't warranted. Bumping the score significantely isn't particularly useful as it could generate false positives, and bumping it just a bit would likely continue to allow joe-job blowback through defeating the purpose of watermarking.
My inbound watermark settings:
Use Watermarking yes
Add Watermark yes
Check Watermarks With No Sender yes
Treat Invalid Watermarks With No Sender as Spam nothing
Check Watermarks To Skip Spam Checks yes
Watermark Secret CBJ-SomeSecretThingHere
Watermark Lifetime 604800
Watermark Header X-CBJ-MailScanner-Watermark:
Any changes I should make?
Kevin Miller Registered Linux User No: 307357
CBJ MIS Dept. Network Systems Admin., Mail Admin.
155 South Seward Street ph: (907) 586-0242
Juneau, Alaska 99801 fax: (907 586-4500
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