Google is actively promoting DMARC. See the articles and links below: - all from Google, and about Google's use, and promotion of, DMARC:
Google also checks ALL INCOMING E-MAIL for DMARC records
There are some very specific items which must be setup for DMARC in SmarterMail, or any other MX SERVER:
- DOMAINKEYS (2048 bit - all 1024 bit keys, for everything, were depreciated by Microsoft and US CERT in December, 2014 because of the ability to hack smaller keys easily)
- DKIM
DKIM requires no DNS record
once you set those up, you must setup the following items:
- rDNS - must be setup by the company which provides your STATIC IP ADDRESSES
- SPF - must be setup in YOUR PRIMARY DNS SERVER
- DOMAINKEY entries in DNS - there are THREE TOTAL
- the DOMAIN KEY, a TXT record
- which contains THREE RECORDS, shown as:
- Entered in DNS as:
- DMARC RECORD: must be setup in your PRIMARY DNS SERVER
- Not all DNS servers support 2048 bit DMARC records, but anything smaller than 2048 bit will be rejected by GOOGLE, so plan on updating your DNS if it doesn't support 2048 bit TXT records - which is how a DMARC record is added - as a TXT record.
- Microsoft DNS does support 2048 bit TXT records
Note about DNS SERVERS: you should have at least TWO, with the new standard being THREE. The PRIMARY will auto-feed everything to the 2nd and 3rd DNS servers.
Here's my DMARC RECORD:
v=DMARC1; p=reject; sp=reject; rua=mailto:dmarc@chicagonettech.com!10m; ruf=mailto:dmarc@chicagonettech.com!10m; rf=afrf; pct=100; ri=86400
It's entered as a TXT record in DNS.
the e-mail address, dmarc@chicagonettech.com accepts the DMARC reports and forwards them directly to DMARCIAN at dmarcian.com, which translates the data and sends me reports on anyone trying to hack or spoof my e-mail.
we've had ZERO PROBLEMS with DMARC and have been running it for two years now - on ALL HOSTED DOMAINS.
DMARC will save your MX server's reputation and keep you out of trouble!
==================================
Google Apps features that protect against spoofing
Spoofing occurs when a spammer forges the From address on a mail message so that the message appears to come from a domain that didn’t actually send it. Both Postini and Google Apps provide several tools to protect against spoofing:
- Creating an Sender Policy Framework (SPF) record
- Adding a DomainKeys Identified Mail (DKIM) digital signature
- Creating a Domain-based Message Authentication, Reporting, and Conformance (DMARC) record
- Allowing messages from certain IP addresses only within the domain
For message senders, these tools let the sender provide information to recipients to help the recipients identify if someone is spoofing that sender’s email address. For message recipients, these tools provide a way to identify incoming spoofed messages.
See: https://support.google.com/a/answer/6081583?hl=en
==================================
Control unauthenticated mail from your domain
Emails not delivered to Gmail?
If you sent an email to a Gmail user and got an automatic bounce message that says, "Unauthenticated email from [email domain] is not accepted due to domain's DMARC policy,” see the options below for more information:
- If you sent the email using Gmail, learn how to fix your settings in Gmail.
- If you sent the email using a different email application, try looking for a setting in your email application that controls the server used to send messages (the “outgoing” server). Change this setting so that you’re using the server that matches the email address you want to send from. If that doesn’t work or you need more help, contact the email provider for your email address.
To help fight spam and abuse, Gmail uses email authentication to verify if a message was actually sent from the address it appears to be sent from. As part of the DMARC initiative, Google allows domain owners to help define how we handle unauthenticated messages that falsely claim to be from your domain.
What you can do
Domain owners can publish a policy telling Gmail and other participating email providers how to handle messages that are sent from your domain but aren’t authenticated. By defining a policy, you can help combat
phishing to protect users and your reputation.
On the DMARC website, learn how to publish your policy, or see the instructions for Google Apps domains.
Here are some things to keep in mind:
- You'll receive a daily report from each participating email provider so you can see how often your emails are authenticated and how often invalid emails are identified.
- You might want to adjust your policy as you learn from the data in these reports. For example, you might adjust your actionable policies from “monitor” to “quarantine” to “reject” as you become more confident that your own messages will all be authenticated.
- Your policy can be strict or relaxed. For example, eBay and PayPal publish a policy requiring all of their mail to be authenticated in order to appear in someone's inbox. In accordance with their policy, Google rejects all messages from eBay or PayPal that aren’t authenticated
==================================
Prevent outgoing spam with DMARC
Add a DMARC record
Create the record
Once SPF and DKIM are in place, you configure DMARC by adding policies to your domain's DNS records in the form of TXT records (just like with SPF or ADSP).
Important: Before creating a DMARC record for your Google Apps domain, you must first
set up DKIM authentication. If you fail to set up DKIM first, email from services such as Google Calendar will fail mail authentication and will not be delivered to users.
Follow the instructions to create a TXT record with the appropriate name and value, using the specific instructions for popular domain hosts. The TXT record name should be "_dmarc.your_domain.com." where "your_domain.com" is replaced with your actual domain name. You can also review the limitations with some domain hosts.
https://support.google.com/a/answer/2466563?hl=en
==================================
Prevent outgoing spam with DMARC
Understand DMARC
Prevent outgoing spam with DMARC
Understand DMARC
Overview
Spammers can sometimes forge the "From" address on mail messages so the spam appears to come from a user in your domain. To help prevent this sort of abuse, Google is participating in DMARC.org, which gives domain owners more control over what Gmail does with spam emails from their domain.
Google Apps follows the DMARC.org standard and allows you to decide how Gmail treats unauthenticated emails coming from your domain. Domain owners can publish a policy telling Gmail and other participating email providers how to handle unauthenticated messages sent from their domain. By defining a policy, you can help combat phishing to protect users and your reputation.
Prerequisites
Please note, you must send all mail through your own domain for DMARC to be effective. Mail sent on your behalf through third-party providers will appear unauthenticated and therefore may be rejected, depending upon your policy disposition. To authenticate mail sent from third-party providers, either share your DKIM key with them for inclusion on messages or have them relay mail through your network.
If you're a domain owner, you'll first need to configure SPF records and DKIM keys on all outbound mail streams. DMARC relies upon these technologies to ensure signature integrity. A message must fail both SPF and DKIM checks to also fail DMARC. A single check failure using either technology allows the message to pass DMARC. See the corresponding SPF and DKIM sections of the DMARC specification for example messages filtered by these tools.
https://support.google.com/a/answer/2466580?hl=en
==================================
The response will show you all aspects of your MX server configuration and tell you what needs to be fixed to make SPF, rDNS, DOMAINKEYS, DKIM and/or DMARC work properly.
Here's a portion of a response, showing everything working properly for one of my customer's SmarterMail servers:
Publication: RFC 4408 |
SPF Records |
SmarterMail Check: |
Passed |
ARSoft Check: |
Passed |
SpamAssassin Check: |
Passed |
SPF DNS Location: |
Click Here: REDACTED.com |
SPF Record in TXT (TYPE 16): |
v=spf1 mx a ip4:999.999.999.99 ip4:999.999.999.998 ~all
IP ADDRESSES REDACTED |
(TYPE 16) Syntax: |
Passed |
SPF Record in SPF (TYPE 99): |
Not Found - Learn about SPF (TYPE 99) Click Here |
Publication: RFC 4406 |
Sender ID |
Sender ID Check: |
Passed |
Sender ID Record: |
Uses SPF implementation above |
Publication: RFC 4870 |
Domain Keys Additional Information (Obsolete) |
Tag |
Value |
Key Algorithm: |
a=rsa-sha1 (must be SHA256 as of 1 April, 2016) |
Canonicalization: |
c=simple |
Query Method: |
q=dns |
Domain Name: |
d=REDACTED.com |
Selector: |
s=secure |
Signed Headers: |
h=received:from:to:subject:date:reply-to:message-id:mime-version :content-type:x-originating-ip |
Signature Data: |
b=Uss8YljZmrNpN04tLTvKWlMsHrZE3M515QzkZ/ld9fWEtlzEF6TBE7omJWqFhSbpw RGbuW8FKqZ14B2ZVEOxGs7MzPl5rEvnvdmIdBCldAF2WYZu6AtVxu0OY2Rg6JPNI7 tES8Idrz8qPaXVGS17Eagv/bq029TDcBMhA9qYOLXMhUClmVTxzCQXF3k8lxkrG4t D3gePrONKNPkNaqQb8FNP7XZCNfqWlXpEAvUXEkLkrnsTn2/xT4Q+/xsIn2E+n20x s8rROmS0fE+PEidonX8f6PSVNAXONfyyZYGSUBHRxjaKrYvlSh9oCAGEhCS/B58S0 EcmZ4Op82ZhlmKvvQ== |
Domain Keys Check (Obsolete) |
Signature Found: |
Yes |
SM Signature Verification: |
Passed |
From Signed: |
Yes |
Restricted Headers Signed: |
N/A |
Public Domain Key (Obsolete) |
Selector Location: |
Click Here: secure._domainkey.REDACTED.com |
DNS Record Found: |
Yes |
Record Syntax: |
k=rsa;p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtOK1Kr3N219+0cklMJzYVRzaleNWpqsfo5bOQDQ5sJvOBvO/TdhdgoqF4eCWPDGdrP86fKPvCp1TlgGA+2PI3Yy7FZtnTRWQIoYDCbcw4ZhPbB76PhYq72D7IAIP9eu1/4s11ni95AeP+eKzBCvkmXA3ogGm1kjoD/k404NzRh8r5Gkh7K1TUSjTIL/quwHKNGWUd78Btyv6oGByug+HZD+3RlHqX+E4gelGUQCKBJZS5xmumYRl9hehcjpDNzDeFxWwaSoR495z5QtllcyIKJdJYCB9pjZeLVMr8mecfcaruaPmmjLRYRDZQk7sDQwjsyC5KVTk3GvG1scIEk1pNQIDAQAB |
Key Size: |
2048 |
Publication: RFC 6376 |
DKIM Signature Additional Information |
Tag |
Value |
Version: |
v=1 |
Key Algorithm: |
a=rsa-sha256 |
Canonicalization: |
c=simple/simple |
Domain Name: |
d=REDACTED.com |
Selector: |
s=secure |
Signed Headers: |
h=x-originating-ip:content-type:mime-version:message-id:reply-to :date:subject:to:from |
Body Hash: |
bh=SK/6XswJedgxUWxICi4PZiREQpskF8cDfsmKgaVOIP8= |
Signature Data: |
b=OhHUpPHEB/7GQKoi4BxxQpnPwQ1pyg0GFK3LfR3g1077B6gn6kbntlCi0V7w18nez e9NI77/8RQHrOweRo3bpV8HkYggOz6Fd9gThtKnsClGdVNgzG5angapAIs144dexH 4Vr33xCSseVJf2exR5Tktwu7841c3sJ+gUx2W/x4xeyHF2g1CgUXr27F2q45WXrg9 e5uFwYV9m/iWEZ7XFiuJPbVPiLDjZcWrWGL4HriZ3u0RuAwic/GpL+mT1E1ik7ooo iUgcYI/TJJZmbxIxpMF3UOhj4psA37sWydAhTF4AQnq3Xldi/vu3jj29MUyAATzUZ h23+T7ajknywWlSCg== |
Publication: RFC 6376 |
DKIM Check |
Signature Found: |
Yes |
SmarterMail DKIM Test: |
Passed |
LimiLabs DKIM Test: |
Passed |
SpamAssassin DKIM Test: |
Passed |
From Signed: |
Yes |
Restricted Headers Signed: |
No |
Public DKIM Key |
Selector Location: |
Click Here: secure._domainkey.REDACTED.com |
DNS Record Found: |
Yes |
Record Syntax: |
k=rsa;p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtOK1Kr3N219+0cklMJzYVRzaleNWpqsfo5bOQDQ5sJvOBvO/TdhdgoqF4eCWPDGdrP86fKPvCp1TlgGA+2PI3Yy7FZtnTRWQIoYDCbcw4ZhPbB76PhYq72D7IAIP9eu1/4s11ni95AeP+eKzBCvkmXA3ogGm1kjoD/k404NzRh8r5Gkh7K1TUSjTIL/quwHKNGWUd78Btyv6oGByug+HZD+3RlHqX+E4gelGUQCKBJZS5xmumYRl9hehcjpDNzDeFxWwaSoR495z5QtllcyIKJdJYCB9pjZeLVMr8mecfcaruaPmmjLRYRDZQk7sDQwjsyC5KVTk3GvG1scIEk1pNQIDAQAB |
Key Size: |
2048 bits |
Draft Publication: DMARC Base-00-02 |
DMARC Check |
Record Syntax: |
Passed |
DKIM Test: |
Passed |
SPF Test: |
Passed |
ADKIM Test: |
Passed |
ASPF Test: |
Passed |
RUA Test: |
Passed |
RUF Test: |
Passed |
DMARC Passed: |
Yes |
DMARC Record Location: |
Click Here: _dmarc.REDACTED.com |
DMARC Record: |
v=DMARC1; p=none; sp=none; adkim=s; aspf=s; rua=mailto:dmarc@REDACTED.com; ruf=mailto:dmarc@REDACTED.com; rf=afrf; pct=100; ri=86400 |
Publication: RFC 5617 |
ADSP (Author Domain Signing Policy) Check (HISTORIC) |
ADSP Record: |
dkim=all; |
ADSP Record Syntax: |
Passed |
ADSP Record Location: |
Click Here: _adsp._domainkey.REDACTED.com |
Acceptance of Abuse Address |
abuse@mydatapage.com |
Passed |
Spam Assassian Results |
Content analysis details: (You scored -2.7 points, 5.0 or higher is considered to be spam)
|
Pts |
Rule Name |
Description |
-0.0 |
SPF_PASS |
SPF: sender matches SPF record |
-0.7 |
RP_MATCHES_RCVD |
Envelope sender domain matches handover relay domain |
-1.9 |
BAYES_00 |
BODY: Bayes spam probability is 0 to 1% |
|
|
[score: 0.0000] |
0.0 |
HTML_MESSAGE |
BODY: HTML included in message |
-0.1 |
DKIM_VALID_AU |
Message has a valid DKIM or DK signature from author's |
|
|
domain |
-0.1 |
DKIM_VALID |
Message has at least one valid DKIM or DK signature |
0.1 |
DKIM_SIGNED |
Message has a DKIM or DK signature, not necessarily valid |
0.0 |
TVD_SPACE_RATIO |
No Description available. |
Bruce Barnes
ChicagoNetTech Inc
brucecnt@comcast.net
Phonr: (773) 491-9019
Phone: (224) 444-0169
E-Mail and DNS Security Specialist
Network Security Specialist
Customer Service Portal: https://portal.chicagonettech.com
Website: https://www.ChicagoNetTech.com
Security Blog: http://networkbastion.blogspot.com/
Web and E-Mail Hosting, E-Mail Security and Consulting