Business mail platform · Rackspace Email
Verifying addresses at Rackspace Email domains
Can you verify addresses at domains behind Rackspace Email?
Depends on the domainIt depends on the company. Domains behind Rackspace Email are probed like any other.
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Rackspace Email answers for the company's own mail rules, so the checker treats every domain on its own: it offers a random address first, and if that is accepted the domain is catch-all and results come back risky ("Accepts all addresses"). Otherwise your address gets a per-mailbox answer. It always checks the syntax, the domain's MX records, disposable domains and role addresses such as info@ first.
Mailbox existsMailbox not foundAccepts all addressesCompany domains whose MX records point at emailsrvr.com are hosted at Rackspace Email. Rackspace Email documents a catch-all option, and where an admin turns it on every address at the domain looks deliverable. Our checker probes each domain on its own: it offers a random address that can't exist first, and a domain that accepts it comes back risky as catch-all; otherwise your address gets a per-mailbox answer.
Live DNS snapshot: emailsrvr.com
Checked 26 October 2026, 07:05 UTCemailsrvr.com is an MX host suffix, not a mail domain, so this is emailsrvr.com: a domain whose mail runs through Rackspace Email. Read from DNS at the time shown and refreshed at most once a day.
- 10
mx1.emailsrvr.comRackspace Email - 20
mx2.emailsrvr.comRackspace Email
First MX host belongs to Rackspace Email.
v=spf1 ip4:108.166.43.0/24 ip4:146.20.86.8 ip4:146.20.161.0/25 ip4:161.47.34.7 ip4:173.203.187.0/25 ip4:184.106.54.0/25 ip4:204.232.172.40 ~allp=none: meets the requirement, but blocks nothing.
v=DMARC1; p=none; rua=mailto:q8ixamfp@ag.dmarcian.com,mailto:dmarc_agg@dmarc.250ok.net,mailto:rackspace@rua.agari.com; ruf=mailto:dmarc_fr@dmarc.250ok.net,mailto:rackspace@ruf.agari.com; fo=1;Look up any other domain with the MX lookup or the email provider lookup.
Rackspace Email at a glance
| Operated by | Rackspace US, Inc., San Antonio, Texas, USASource: Rackspace legal information |
|---|---|
| MX hosts | mx1.emailsrvr.com (priority 10) and mx2.emailsrvr.com (priority 20)Source: Rackspace docs: DNS records for Cloud Office email |
| Address rule | Rackspace marks its catch-all addressing feature as sunset; since April 2022 no new configurations, existing ones stay until disabledSource: Rackspace docs: feature changes and removal |
| Address rule | Rackspace says its system does not filter catch-all addresses for spamSource: Rackspace docs: catch-all address |
Rackspace stopped new catch-all setups in 2022
Rackspace tells customers to use `mx1.emailsrvr.com` and `mx2.emailsrvr.com` and no other MX records.
Its feature-change notice says catch-all configurations have not been available to new setups since April 2022, but existing ones remain until disabled. So most domains here are not catch-all, but older ones can be. Check each domain.
What our checker does behind Rackspace Email
SimpleVerifier doesn't skip or special-case Rackspace Email. For each company domain it offers a random address that can't exist, then your address, and disconnects without sending. If the random address is accepted, the domain is catch-all and its results come back risky with "Accepts all addresses". If it is rejected, your address gets a real answer for that mailbox.
Consumer mailboxes are a separate case; see the Gmail and Yahoo pages. Domains behind Rackspace Email are treated like any company domain.
Cleaning a list full of Rackspace Email domains
Split the list by domain, not by platform. Two companies on Rackspace Email can behave in opposite ways, so a catch-all result at one says nothing about the next. The bulk catch-all checker finds which domains in a list accept everything before you spend time on single addresses.
For catch-all domains, keep addresses with recent replies or sign-ups and send the rest in a small first batch, suppressing anything that hard-bounces. For per-mailbox domains, trust the verdict: invalid addresses will bounce, and valid ones were accepted by the company's own directory. Accept-all vs unknown results covers the difference.
Common questions
- Can you verify addresses at domains behind Rackspace Email?
- It depends on the company. Domains behind Rackspace Email are probed like any other. Rackspace Email answers for the company's own mail rules, so the checker treats every domain on its own: it offers a random address first, and if that is accepted the domain is catch-all and results come back risky ("Accepts all addresses"). Otherwise your address gets a per-mailbox answer. It always checks the syntax, the domain's MX records, disposable domains and role addresses such as info@ first.
- How do I know if a company uses Rackspace Email?
- Look up the domain's MX records. A first MX host ending in emailsrvr.com means mail goes through Rackspace Email. The email provider lookup and MX lookup tools show it for any domain.
- Are domains behind Rackspace Email catch-all?
- Some are and some aren't; it depends on how each company configured Rackspace Email. A verifier can tell by offering a random address that can't exist: if the domain accepts it, the domain is catch-all and single addresses there can't be confirmed.
- What is emailsrvr.com in an MX record?
- It is Rackspace Email. Rackspace documents mx1.emailsrvr.com and mx2.emailsrvr.com as the MX values.
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