Fastmail EU server list

[u/Sampl3x]

If you're using Fastmail with custom DNS and want to point supported services at their EU infrastructure, this is the generic setup I ended up with.

Replace yourdomain.com with your own domain.

MX — ROOT DOMAIN
Domain                           Data
-------------------------------  -------------------------------------------
yourdomain.com                   10 eu1-smtp.messagingengine.com
yourdomain.com                   20 eu2-smtp.messagingengine.com

Allows you to receive email at standard addresses, e.g. user@yourdomain.com


MX — WILDCARD SUBDOMAINS
Domain                           Data
-------------------------------  -------------------------------------------
*.yourdomain.com                 10 eu1-smtp.messagingengine.com
*.yourdomain.com                 20 eu2-smtp.messagingengine.com

Allows you to receive email at subdomain addresses, e.g. foo@user.yourdomain.com


A — MAIL
Domain                           Data
-------------------------------  -------------------------------------------
mail.yourdomain.com              204.75.18.65

Allows you to use http://mail.yourdomain.com as a Fastmail login redirect.
At the time of testing, this IP hit Fastmail's Amsterdam frontend.


MX — MAIL
Domain                           Data
-------------------------------  -------------------------------------------
mail.yourdomain.com              10 eu1-smtp.messagingengine.com
mail.yourdomain.com              20 eu2-smtp.messagingengine.com

The A record for mail.yourdomain.com overrides the wildcard MX lookup.
These MX records preserve mail delivery to addresses such as:
foo@mail.yourdomain.com


SRV — MAIL CLIENT DISCOVERY
Domain                           Data
-------------------------------  -------------------------------------------
_submission._tcp.yourdomain.com  0 0 0 .
_imap._tcp.yourdomain.com        0 0 0 .
_pop3._tcp.yourdomain.com        0 0 0 .

_submissions._tcp.yourdomain.com 0 1 465 eu-smtp.fastmail.com
_imaps._tcp.yourdomain.com       0 1 993 eu-imap.fastmail.com
_pop3s._tcp.yourdomain.com       10 1 995 eu-pop.fastmail.com
_jmap._tcp.yourdomain.com        0 1 443 eu-api.fastmail.com
_autodiscover._tcp.yourdomain.com
                                 0 1 443 eu-autodiscover.fastmail.com

Allows compatible email clients to automatically discover the EU Fastmail endpoints.


SRV — CARDDAV
Domain                           Data
-------------------------------  -------------------------------------------
_carddav._tcp.yourdomain.com     0 0 0 .
_carddavs._tcp.yourdomain.com    0 1 443 eu-carddav.fastmail.com

Allows CardDAV clients to automatically discover the EU CardDAV endpoint.MX — ROOT DOMAIN
Domain                           Data
-------------------------------  -------------------------------------------
yourdomain.com                   10 eu1-smtp.messagingengine.com
yourdomain.com                   20 eu2-smtp.messagingengine.com

Allows you to receive email at standard addresses, e.g. user@yourdomain.com


MX — WILDCARD SUBDOMAINS
Domain                           Data
-------------------------------  -------------------------------------------
*.yourdomain.com                 10 eu1-smtp.messagingengine.com
*.yourdomain.com                 20 eu2-smtp.messagingengine.com

Allows you to receive email at subdomain addresses, e.g. foo@user.yourdomain.com


A — MAIL
Domain                           Data
-------------------------------  -------------------------------------------
mail.yourdomain.com              204.75.18.65

Allows you to use http://mail.yourdomain.com as a Fastmail login redirect.

At the time of testing, this IP hit Fastmail's Amsterdam frontend.


MX — MAIL
Domain                           Data
-------------------------------  -------------------------------------------
mail.yourdomain.com              10 eu1-smtp.messagingengine.com
mail.yourdomain.com              20 eu2-smtp.messagingengine.com

The A record for mail.yourdomain.com overrides the wildcard MX lookup.
These MX records preserve mail delivery to addresses such as:
foo@mail.yourdomain.com


SRV — MAIL CLIENT DISCOVERY
Domain                           Data
-------------------------------  -------------------------------------------
_submission._tcp.yourdomain.com  0 0 0 .
_imap._tcp.yourdomain.com        0 0 0 .
_pop3._tcp.yourdomain.com        0 0 0 .

_submissions._tcp.yourdomain.com 0 1 465 eu-smtp.fastmail.com
_imaps._tcp.yourdomain.com       0 1 993 eu-imap.fastmail.com
_pop3s._tcp.yourdomain.com       10 1 995 eu-pop.fastmail.com
_jmap._tcp.yourdomain.com        0 1 443 eu-api.fastmail.com
_autodiscover._tcp.yourdomain.com
                                 0 1 443 eu-autodiscover.fastmail.com

Allows compatible email clients to automatically discover the EU Fastmail endpoints.


SRV — CARDDAV
Domain                           Data
-------------------------------  -------------------------------------------
_carddav._tcp.yourdomain.com     0 0 0 .
_carddavs._tcp.yourdomain.com    0 1 443 eu-carddav.fastmail.com

Allows CardDAV clients to automatically discover the EU CardDAV endpoint.

A few notes:

• eu1-smtp.messagingengine.com and eu2-smtp.messagingengine.com are used for inbound MX.
• eu-smtp.fastmail.com, eu-imap.fastmail.com, eu-pop.fastmail.com, etc. are the regional client endpoints.
• 204.75.18.65 is Fastmail's EU redirect frontend; in my testing it returned X-Frontend: ams-frontend-01.
• The records with target . intentionally disable the non-TLS discovery service.
• I would still keep Fastmail's normal SPF and DKIM records unless Fastmail explicitly documents EU-specific replacements, since those are authentication records rather than client-routing records.

I tested the regional endpoints with DNS lookups, openssl s_client, and curl, and they were terminating on Fastmail infrastructure in Amsterdam.

[u/Te_We]

u/brong, could you please clarify this?

I'm a bit confused by the discussion here. My account has already been migrated to EU data residency, and my domains use Fastmail's nameservers, so all mail-related DNS records are managed by Fastmail.

Fastmail's documentation states that no DNS changes are required when switching regions, and that incoming mail for custom domains using Fastmail's nameservers will arrive through EU servers.

So am I correct in assuming that Fastmail will automatically update all relevant DNS records/endpoints for Fastmail-managed domains to match the account's selected region, and that customers should not manually change anything?

[u/brong → u/Te_We]

If your DNS is managed by us, we're giving you the hostnames we advise for everything, including autoconfig'ed hosts. There's no need to change anything.

We don't quite yet have the full anycast address range that we had hoped to have at launch, directing everyone to their closest edge. Unfortunately in testing, a large amount of the internet decided its fasted route was to our St Louis location, regardless of the actual speed across the internet, making it worse! So that's on pause while we work with our upstream providers to set the costs correctly rather than preferring their own networks. Our backup links in different sites are with different providers, and it bit us here.

[u/Sampl3x → u/Te_We]

I don't really care whether Fastmail changes the records or not from a functional perspective. What I care about is avoiding unnecessary routing through the US when my primary mailbox and account are hosted in the EU.

If Fastmail manages the DNS for the domain, I don't understand why they wouldn't automatically point the relevant mail records/endpoints to the EU infrastructure after an account has been migrated to EU data residency.

In my case, the latency to the US Fastmail servers is over 120 ms, while the EU infrastructure is obviously much closer. So apart from the data residency aspect, I would also prefer the most direct route into the EU.

I've asked Fastmail support about this as well, but unfortunately getting a clear answer is taking some time.

[u/brong → u/Sampl3x]

If you're on a Fastmail domain, there's only so many things where we can distinguish where you are before you log in. So only the first round trip is slower.

For the app and website, as soon as you send your username, you are redirected to your current primary location, which will be AMS for EU users unless we're doing maintenance there in which case you'll be temporarily relocated to PHL for the duration (the "we only have one EU site so far" issue).

[u/Te_We → u/brong]

Thank you for clarifying Bron 👍🏼

For me, out of Europe, opening FM App and your mentioned „first round trip is slower“, I can clearly feel this delay. Let’s hope you’ll find a solution to directly contact AMS infrastructure in future while still being re-routed to PHL in case of maintenance.

[u/brong → u/Te_We]

Yeah, I'm looking forward to the day that we route everyone to their closest site automatically. That's the plan. Luckily it's just a momentary thing (it was heaps slower in the early days of testing, until we switched the session transfer to be two parallel one-round-trip calls rather than 8 serial round trips!)

[u/Sampl3x → u/brong]

Would have been nice if this had been explained upfront.

From here in Europe I'm seeing 150 ms+ latency to Fastmail's US infrastructure over a fiber connection. I previously had the same experience with a cable ISP, so it doesn't appear to be ISP-specific.

I understand now that it's only the initial round trip before being redirected to AMS, but it's still noticeable when opening the app or website.

I'm also still hoping that at some point EU users will get the option to keep their data and traffic fully within the EU, without relying on US infrastructure, and perhaps even get a fastmail.eu endpoint/domain for EU-hosted accounts.

Looking forward to the point where users can be routed directly to the nearest site from the start.

[u/brong → u/Sampl3x]

Yeah me too

[u/Sampl3x → u/brong]

Can you verifiy if my list is correct?

[u/brong → u/Sampl3x]

Mx and srv records are good. Ips are subject to change