Mailgun forwarding can result in your domain being treated as spam | Hacker News Reader

Mailgun forwarding can result in your domain being treated as spam

blog.rajivm.com

69 pointsrajivm31 comments

Hi All,

Mailgunner here, a couple of notes:

* The case outlined in this blog post is related to incoming email forwarding feature, not Mailgun outbound sending.

* General email forwarding case does not break Mailgun's DKIM signature.

* Forwarding is tricky as long as it modifies content and we have lots of edge cases with our customers, and we are always working on improving on edge cases like this one.

* This is an edge case where the email has been forwarded from Mailchimp -> Mailgun -> Gmail and we have some conflicting content with Mailchimp's original email causing the DKIM signature failure.

* Mailgun sending pipeline team is looking at the issue to get more detail about that.

Thanks everyone!

Firstly, thank you for responding.

I've also been affected by this. Any course of action that I could take? I've been using the forwarding feature for a while, my setup is simply Cloudflare DNS -> Mailgun -> Gmail. Would be happy to provide my domain name if you need it!

No prob at all, the best way is to submit us a ticket, so we can get in contact with you and update when this issue is resolved.

The real question is, can Mailgun assist with contacting Google re: affected domains and helping clear the penalty that has been imposed.

I had some problem with my mailgun-sent emails being marked as spam. But I was only using the free plan, since I only send 25 mails a week or so.

I didn't have any problems with DKIM, though, or SPF. My problem was having to use a shared IP (part of the free plan) and sometimes getting an IP that was in one of the spam blacklists.

I'd add that https://www.mail-tester.com/ was INCREDIBLY useful when I was trying to diagnose problems.

Do you have to pay for the static ip to get around this or is just putting in a credit card sufficient?

you're going to need to buy the IP from whoever you're sending with or ask to be put on a warmed up IP shared with other legit senders.

Mailgun charges $59/month for a dedicated IP.

http://www.mailgun.com/pricing

You just saved my ass with that link https://www.mail-tester.com/

Our company's email was 1.7/10 made some quick changes and now I'm 8.9

All DNS issues I thought I wouldn't have because I'm on google apps, but I never checked. Fixed now.

I got a 9/10 sending from a Google Apps account because there is one blacklist that has a Google IP in it! Apparently even Google's servers get blacklisted.

Wow. Thanks to that tool, I just found out that my employer's new domain name is on a blacklist. Whoops.

I just tested my email system and 10/10 so there is not much more that I can do. The problem is that I am losing a certain percentage of emails (~2 to 3%) to customers in a completely non-deterministic manner. Microsoft is the worst offender, but it happens with yahoo and gmail too. I am beginning to think that filters have a randomization factor in them just to drive me insane.

As an aside, since Mailgun was bought by Rackspace, customer service, reliability, and their ability to fix issues quickly has seemingly taken a huge hit.

I couldn't have been happier with Mailgun a year or so ago. Currently, I have a bug filed and reported to them that impacts our business (as well as many others I'm sure), that has been outstanding since July. They still haven't acknowledged it - and all I get is stock responses linking to their broken documentation

Can anyone reccomend any alternatives? When we set up OpenRent in 2012, Mailgun was the best. Now I'm much less convinced - any feasible alternatives would be much appreciated.

Honestly we are the same team since Mailgun was founded, all pre-acquisition employees are happily working on the product. The only difference is that we've become bigger since then, and some issues may slip through the cracks because of overall volume.

Can you send me the ticket# so I can take a look?

I appreciate my experience is anecdotal, but I'm pretty sure issues used to be read and responded to by technical members of your team - it doesn't feel that way in the last year or so - but the acquisition may have been unrelated of course!

Ticket: #69317 & #154021

I agree with this one. We used to get high quality responses from technical team members. Recent communications haven't been so great. For an example, take a peek at Ticket #154458

In July we identified an issue where Mailgun -> ELB webhook communications are broken under ticket #65535. This has been pending action by Mailgun's team for 4 months now.

http://mandrill.com/ is a good alternative to Mailgun

Unfortunately mandrill does not provide the same type of customizable routing that Mailgun does. Specifically, the ability to set up a forwarding route so that Mailgun handles all of the forwarding is the reason we selected them. To date I have yet to find another email provider that does this and provides API access and multi-domains support.

Another thing to do: if your mailgun email to gmail gets inexplicably marked as spam (as opposed to DKIM failing), try creating a new fresh gmail account and see if email to that gets marked as spam. I was using an old gmail account and its filters were full of cat fur, which was causing stuff to randomly get marked as spam. Spent days playing high-low game deleting parts of the message then adding parts back in trying to figure out which words were triggering it, and it was totally non-deterministic. But once I switched to a fresh gmail account, it worked just fine, and nothing went into the spam folder.

This is what drives me crazy about avoiding spam filters. When I email out quotes to customers (initiated by the customer of course) a certain percentage of emails never make it. There is no rhyme or reason to it (all the obvious things like DKIM, spf, etc are OK), it just seems to be random. Microsoft seems to be the worst offender, but it happens on occasion with gmail and yahoo too. Very frustrating.

Yes, the problem is that many MX servers do not have their spam defences setup in the right order, especially in the case where you reply to someone who has already emailed you:

The recipient's server should always check if your email is authenticated (SPF, DKIM). If so, they should check if their user has emailed you in the past, and if so they should let your email through, to prevent it being marked as a false positive. They should try and do this even if your domain happens to land on a single DNS blacklist (or they should use a quorum of DNS blacklists).

Thanks for the advice, we've had some strange situations where our mails got marked as spam. Currently we only have issues with Outlook. Mails send using Mailgun often get marked as spam, while (the same) mails send using Gmail don't have this problem. Unfortunately, this doesn't seem to happen on all Outlook installations/instances, and Outlook is pretty much a black box to test. Perhaps this could be similar issue (we've had no issues on a clean Outlook installation). Anyone else with similar problems?

"The lesson we learned from this is that we should separate our transactional mail domain from our 'real email'." Yes. Especially if your "transactional email" contains anything which could be interpreted as advertising. Many companies interpret "transactional email" as "spamming our existing customers". Bayesian filters interpret this as spam.

Out of interest, are a lot of people using Mailgun for incoming email forwarding?

We do it because (1) Mailgun is great, and (2) it supports catch-alls, so for example, /(.*)@foo.com/ goes to $1@bar.com. This allows our company to have one Google Apps account, but multiple email domains. Our DNS provider, Gandi, has email forwarding but not support catch-alls.

My understanding is that this is not precisely Mailgun's intended purpose, but that it's fine.

This allows our company to have one Google Apps account, but multiple email domains.

You can do this already with Google Apps by adding more domains to your account. If you are using a forwarding service into your primary domain, you run the risk of not being able to properly detect and filter spam from that forwarder (more configuration is required on gapp's side, which isn't always easy to get right).

We're using Mailgun for other things on that domain. Also, we're on the free version of Google Maps, and email routing is only available for the paid "Google Apps for Work" plan.

I'm curious to know whether you've experienced this only on your account and/or if you tried to replicate this on a different account? Strangely enough I've not had problems with it although I understand the duplicate header might be troublesome..

I have replicated this on another Mailgun account, although that one was of lesser importance.

Ouch... As one who was signing up for mailgun tomorrow, thanks for pointing that out.

It's okay if you're just using it for outgoing mail, incoming+forwarding is where the problem arises.

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