How to fix your Tumblr custom domain name

UPDATE (7/11): I've heard from 3 Tumblr users so far whose sites are down right now, which means this is definitely not a random glitch that only affected my site. According to Tumblr's response, both IP addresses should work, but clearly they're not for some sites. I hope they fix this soon.

twitter feedback about tumblr custom domain issue

UPDATE (7/8): came back up around 11:06 EST on July 8, 2012. In the end, my site was down for about 2 days, while the new IP address was being propagated. Please see Tumblr's response at the end of this post. Apparently, it should never have gone down in the first place, and they're not sure why it did. If you experience the same custom domain glitch as I did, please let me know.

If, like me, you're using a custom domain name for one or more of your Tumblr blogs, your website could be down right now. If that's the case, anyone who visits your site will get We couldn't find the page you were looking for.

Tumblr website with custom domain name not found

I found out that was down thanks to Pingdom. I checked my other Tumblr sites (that aren't being monitored) to determine whether this was a widespread or isolated issue. It turns out it's only affecting, so I logged in to my Tumblr account, then selected "Chez Moncef" from my list of blogs, clicked on "Blog Settings", and this is what I saw:

How to change your domain's A record to fix your Tumblr custom domain name

Following the instructions on the screen, I changed my domain's A Record to point to, but the change won't take effect for at least 8 hours, and up to 72 hours. That's 3 days! In the meantime, you can get the same content at

What's strange is that Tumblr was complaining that was not pointing to Tumblr when its A Record was set to, but that's the IP address that and are pointing to, and they're both up right now. I also went to Tumblr's Explore page and randomly checked several of the Top Editors' sites with custom domain names, and they all point to On a Mac, you can look up a website's IP address in the Terminal app by using the nslookup command:

$ nslookup

Non-authoritative answer:

According to Tumblr's official help document for custom domain names, everyone with a naked custom domain name (i.e. just, without any prefix) needs to point to I could be wrong, but it sounds like everyone who is currently pointing to will have to make a change sooner or later.

Tumblr made a significant change to my blog's settings (and yours could be next) that made my site unreachable. That's pretty much the worst thing that can happen to a site, and Tumblr made the change without any warning whatsoever. Not a single word about this via email, on their Twitter account, their Support blog, the Tumblr Staff blog, or their Engineering blog.

Had I not been monitoring my site, I probably wouldn't have known for weeks about my site being down. Given that I can log in to my affected Tumblr account and view my posts just fine, I would never know that my site was down unless I happened to go to my Blog Settings. The best user experience in this case would be for Tumblr to display a prominent message as soon as I log into my affected account.

What disturbs me is that this isn't the first time they make changes of consequence without proper communication. Earlier this year, I found out — once again by chance — that Tumblr stopped supporting hyphenated tags without warning or remedy. Needing a solution right away, I ended up writing a Rails app called Fix My Tumblr Tags. It's not yet ready for public consumption, but it works, and it's up on GitHub if you want to try it out.

Tumblr's response on July 8, 2012:

Hey Moncef,

I just saw your post related to the A Record for When Tumblr first began, we had everyone point their A Records to, which was an IP address owned by the hosting provider we used back then. Since that time, we have changed hosting providers and have gotten an IP address that Tumblr owns and controls for A Record pointing,

We still have the IP address in place with our old provider and the plan is to keep it in place indefinitely to avoid A Record issues. So, either or should work as a domain A Record. Our Help Center and Settings pages encourage people to move to since that is an IP that Tumblr owns and controls and the one we want to use moving forward.

When we rolled out this change, we had a drop-down banner on the Dashboard for awhile to make users aware of it. I see that you haven't blogged much on Tumblr in recent months, so perhaps the banner came and went before you could see it.

I'm not sure why your domain wasn't working under, but I have verified that it is working under now. I'm very sorry for the trouble. If you need help with this or any other issue, please reach out to us at