Image Hosting on a Different Domain? By Al Iverson A client recently asked, "Are there any deliverability issues with using images hosted on third party CDN whose domain does not match the domain of the sender?" If you're not aware, CDN means Content Delivery Network. A CDN is means of making your web pages and/or web applications load faster, by caching content on multiple servers, then requests for that content can be fulfilled by the nearest or most responsive available server. I might be oversimplifying it a bit, but in my personal experience with various CDNs, that's how they tend to work. Akamai might have been the first one-- they certainly are the one I was first aware of. What our client is asking here, what happens if I send an HTML email message that uses images hosted on a content delivery network that uses a different domain name than my own domain name? Are there any issues with doing that? Is it OK to link to websites or host images on some domain name other than my own? The short answer is, it probably won't cause any issues. As long as the CDN's domain has a good reputation (it isn't blacklisted by any of the big blacklists like the Spamhaus DBL, SURBL, or URIBL), then you're not likely to see delivery rates fall as a result. I'm not aware of ISPs checking for a "domain mismatch" when it comes to where the images are hosted. The domain name for image hosting doesn't have to be the one you're sending from. (Though, from a consumer confidence perspective, it can't hurt to try to ensure that you're using the same domain name all the way down the line.) Also keep in mind that the concern over a domain's reputation doesn't just apply to images. It applies to links as well. At some ISPs (like AOL), it applies to even mentioning the domain name in the body of an email. We had a client recently where a particular mailing of theirs was blocked by AOL, and it was because they were mentioning another company's domain name in the body of their email message. That domain name was on AOL's blocked list due to some unspecified prior bad act (we assume). Even though it wasn't a link, just mentioning this domain name in the email message was enough to result in the message being blocked. Certainly, it was easy enough to address after the fact, but this kind of thing isn't always easy to proactively monitor ahead of time, especially considering that it's not your domain name. (A client using the Return Path inbox tools suite to monitor ongoing deliverability rates would have seen this issue pretty quickly based on the inbox rate results for this particular campaign.) One final note, some CDNs allow you to use your own domain name, mapped to their network by way of various configuration options (like, CNAME'ing an image domain to a hostname owned by the CDN). If that's an option, I'd recommend it. It sidesteps most of the potential domain reputation concerns, segregating things so that there are fewer references to other domains in the body of the email message or HTML code, reducing the chances that somebody else's domain reputation issue could impact you. Source: http://blog.exacttarget.com/blog/al-iverson/image-hosting-on-a-different-domain An important user comment:
One can also put images inline in the mail message and refer to that in the HTML code. I wonder how that affects delivery.
I've personally never tried that, Although I've seen it done on some stuff that has inboxed my gmail. What I do is use the domain I'm mailing from to point to my images (The mailing server doesn't host them) I use a Location heard to point to the real URL so the domain in the content of the email is still mine but the image is hosted else where.
