Sending messages to outlook/hotmail issue

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clifff
Posts: 2
Joined: Thu May 30, 2019 12:02 am

Sending messages to outlook/hotmail issue

Postby clifff » Thu May 30, 2019 12:29 am

Dear all,

We are facing a strange behaviour with our brand new installation of zimbra 8.8.12 under CentOS7.
I´ve been looking for a possible answer within the forums with no luck.

The set up:

We have a single server implementation used to serve accounts from different domains.

The main domain is example.com and has configured all the needed SPF, DKIM, MX, A and DMARC records. If we send a mail from some of the accounts related with example.com they work properly.
Now, for the different domains, we also have set up all the SPF, DKIM, MX, A and DMARC records within the domain DNS zone. The records seems to be OK, as we have check everything with several online tools such as verifier25, mxtoolbox, etc.

Sample of DNS configs:

main domain: main.com
MX: main.com
IP: 1.1.1.1
DMARC: v=DMARC1; p=none; rua=mailto:abuse@main.com; sp=reject; aspf=r;
SPF: v=spf1 a mx ~all

secondary domain: secondary.com
A: mail.secondary.com (for zimbra virtualhost) pointing to 1.1.1.1
MX: main.com
DMARC: v=DMARC1; p=none; rua=mailto:abuse@secondary.com; sp=reject; aspf=r;
SPF: v=spf1 a mx ~all (also tested with v=spf1 a ip4:1.1.1.1 mx ~all)
DKIM: key._domainkey v=DKIM1;k=rsa;p=blablabla

The problem:
The thing is that, when we send a mail from some of the different domains to hotmail/outlook, the mail is marked as junk. The funny thing is that if we forward the previous sent mail from the same address to the same hotmail/outlook, then the email arrives OK.

It seems to happen only with outlook/hotmail. If we exchange mails between zimbra accounts everything is OK, and also if we send to gmail/gsuite and other providers.

The reports from verifier25 and others gives us all pass and a score of -2

We have also use the "microsoft remote connectivity tool" in order to dig some extra info getting these values:
X-Forefront-Antispam-Report EFV:NLI; (no description about these values in the technet forums but I guess that NLI is "not listed")
BCL 0;PCL:0;RULEID:(2390118)(5000113)(711020)(4605104)(610169)(650170)(651021)(8291501072);SRVR:SN1NAM02HT082; (BCL 0 is a good value, PCL between 1-3 is neutral and 4-8 suspicious, so I guess 0 is OK) Then RULEID I have no idea about these codes

The thing is, could be just a problem with the Microsoft spam filters?
Other thing that I´ve read is that microsoft checks the PTR. In this case, as in other threads was said, I can only have one PTR which is related with the main zimbra domain.

Any idea of what could be happening?

If needed I can supply the headers from some emails marked as junk.

Thanks in advance


jholder
Zimbra Employee
Zimbra Employee
Posts: 4686
Joined: Fri Sep 12, 2014 10:00 pm

Re: Sending messages to outlook/hotmail issue

Postby jholder » Thu May 30, 2019 4:39 am

clifff wrote:The thing is, could be just a problem with the Microsoft spam filters?


No. Just ask em. (I joke)

There are hundreds of ways this can happen, and some will not be in your control. In general what you want to do is improve your reputation of the outgoing message so much, that it off sets any flags.
But if it's Microsoft only, you're gonna have to look at those reasons and address them. individually.

I would be interested to know if you have the same problem with gmail.
clifff
Posts: 2
Joined: Thu May 30, 2019 12:02 am

Re: Sending messages to outlook/hotmail issue

Postby clifff » Thu May 30, 2019 10:12 am

jholder wrote:I would be interested to know if you have the same problem with gmail.


Hi, thanks for the answer.

Nope, at this moment we are not facing the problem with Gmail. The emails are been recived ok.

The thing is that I've contacted Microsoft using some of the contact forms and they replied that our ip is ok... At this point I dont know what to do or to think, if it is our fault or microsoft's fault

Thanks
mrdash
Posts: 4
Joined: Fri Jun 14, 2019 6:49 am

Re: Sending messages to outlook/hotmail issue

Postby mrdash » Fri Jun 14, 2019 7:17 am

I am having somehow same kind of problem. I have a single server with 5 domains. When user1@domain1.com sends to user2@domain1.com from outlook mail client the mail is delivered to junk of user2 but web UI it is working fine. The peculiar thing is the problem is happening for 3-4 users (as source) in the server and it is for random emails. No parten I found between the emails yet.

In attachment it is saying it is blocked due to image but everyone is using same one and why small logo is creating spam alert? Any suggestion is highly appreciated.
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