IONOS
Publish your eusend DNS records at IONOS — the one-click path that skips the form entirely, and the Host name field that takes the selector only.
IONOS is a Domain Connect provider, so you probably do not have to do any of this by hand.
Try the automatic route first. On the domain page in eusend, a Set up automatically button appears when your DNS provider can publish the records for us — IONOS can. You are sent to IONOS, you approve the change on their own screen, and you come back done. We never hold credentials for your zone. The manual steps below are the fallback.
Add the records
Open DNS settings
Log in to IONOS and go to Domains & SSL. For the domain you want, click the gear symbol under Actions and select DNS. Click Add record and choose the record type.
DKIM — required
| Field | Value |
|---|---|
| Type | TXT |
| Host name | eusend._domainkey |
| Value | the full v=DKIM1; k=rsa; p=… value from the dashboard |
| TTL | leave as-is |
Click Save.
DMARC — recommended
| Field | Value |
|---|---|
| Type | TXT |
| Host name | _dmarc |
| Value | v=DMARC1; p=none; rua=mailto:dmarc@acme.com |
Use an address you actually read for rua — see DMARC.
Return-Path — optional, both or neither
| Field | Value |
|---|---|
| Type | TXT |
| Host name | send |
| Value | v=spf1 include:_spf.eusend.dev ~all |
Then a second record:
| Field | Value |
|---|---|
| Type | MX |
| Host name | send |
| Points to | feedback.eusend.dev |
| Priority | 10 |
Publish both and eusend switches your mail to a bounce address on your own domain, so SPF passes and aligns. One without the other does nothing.
IONOS specifics
The Host name field takes the selector only. IONOS's own DKIM documentation
uses s1-ionos._domainkey — the selector and _domainkey, with no domain after
it. Yours is eusend._domainkey. The root domain is @, which none of the eusend
records need.
If IONOS rejects the DKIM value as too long, it is asking you to split it. A single DNS string holds 255 characters and your value is around 400, so break it into two quoted pieces on one line:
echo -n 'v=DKIM1; k=rsa; p=MIIBIjANBgkq…' | fold -w 255 | sed 's/.*/"&"/' | tr '\n' ' 'Paste the result — "first piece" "second piece" — into the Value field. Never
shorten the key to make it fit; resolvers rejoin the pieces, but a truncated key
breaks DKIM permanently.
Your IONOS mailboxes are unaffected. If this domain receives mail through
IONOS, leave the MX records at the apex exactly as they are. The eusend MX record
sits on send, a subdomain with no mail of its own.
TTL is optional. IONOS applies changes to its own nameservers immediately; there is no reason to set one for these records.
Only when IONOS runs your DNS. If the domain's nameservers point elsewhere,
so do your records — check with dig +short NS acme.com.
Check it
dig +short TXT eusend._domainkey.acme.comIf that is empty, check whether the domain ended up in the Host name field:
dig +short TXT eusend._domainkey.acme.com.acme.comOfficial documentation: Managing TXT records and Email authentication with DKIM.