Mailbox provider · Juno
How to verify a juno.com email address
Can you verify @juno.com addresses?
PartlyPartly. @juno.com often refuses checking servers before the mailbox question.
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The checker does probe @juno.com, but its server screens or defers unfamiliar checking connections. A refusal at that stage is about the connection, not the address, so it comes back risky ("Server refused our check" or "Mailbox check unavailable") and never invalid. It always checks the syntax, the domain's MX records, disposable domains and role addresses such as info@ first.
Server refused our checkMailbox check unavailableJuno addresses usually come back inconclusive from a mailbox check. On 13 October 2026 the juno.com mail server mx.dca.untd.com refused our checking server at the greeting stage, citing a Validity Sender Score blocklist listing for the connecting server's IP. A refusal like that says nothing about whether the address exists.
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Live DNS snapshot: juno.com
Checked 6 November 2026, 11:11 UTCRead from DNS at the time shown and refreshed at most once a day. MX says where mail for juno.com goes; SPF and DMARC describe mail sent from it, not whether any one address exists.
- 10
mx.vgs.untd.com - 10
mx.dca.untd.com
v=spf1 ip4:64.136.0.0/20 ip4:64.136.16.0/21 ip4:64.136.22.0/24 ip4:64.136.28.0/22 ip4:64.136.30.0/24 ip4:64.136.32.0/20 ip4:64.136.50.0/23 ip4:64.136.52.0/22 ?allp=none: meets the requirement, but blocks nothing.
v=DMARC1; p=none; pct=10; rua=mailto:[email protected]Look up any other domain with the MX lookup or the email provider lookup.
Juno at a glance
| Operated by | Juno Online Services, Inc. (a United Online service)Source: Juno terms of service |
|---|---|
| Same mailbox system | netzero.net publishes the same MX hosts, mx.dca.untd.com and mx.vgs.untd.com, and sent the identical refusalObserved 13 October 2026 (dig MX) |
| MX hosts | mx.dca.untd.com, mx.vgs.untd.comObserved 13 October 2026 (dig MX) |
| Answer to a made-up address | Connection refused at the greeting: 550 IP in bl.senderscore.com : Access Denied, please see sendersupport.senderscore.netObserved 13 October 2026 (SMTP probe of a made-up recipient, no message sent) |
| Address rule | Once a Juno account is permanently deleted, no one can ever create another account with the same user name, in any capitalisationSource: Juno help: how do I delete my account? |
| Address rule | Juno reserves the right to take or end the use of any user name or email address at any timeSource: Juno terms of service |
| Inactive accounts | Email in inactive or terminated Juno accounts may be deleted under Juno's internal policiesSource: Juno terms of service |
What Juno's server says about a missing mailbox
Juno's server replied 550 IP in bl.senderscore.com : Access Denied, please see sendersupport.senderscore.net. That refusal happened at the greeting stage, before the checking server could name any recipient, so it is a verdict on the connecting server, not on the address. SimpleVerifier returns these as risky with "Mailbox check unavailable" and never as invalid, because treating a refusal as "mailbox not found" would delete real customers from your list.
Servers screen connections this way to keep spam out: missing reverse DNS, a low sending reputation or a blocklist listing are the usual triggers. The same screen applies to every checking service that connects from a shared or new IP, which is why juno.com results differ between verifiers. SMTP verification false positives explains how much to trust each answer.
Juno and NetZero are both United Online services (untd.com), so one blocklist decision covers both domains.
Juno never reissues a deleted user name
Juno says that when an account is [permanently deleted](http://help.juno.com/support/faq/jn/how-delete-acct.html?brand=JN), no one can ever create another account with that user name. Its terms also let it delete mail in inactive accounts under internal policies it does not publish, so a juno.com address does not pass to a new owner but can still go dead.
Juno and NetZero are both United Online services and share mail servers that refused our checker's connection, citing a Validity Sender Score listing. That refusal is about the connecting server, not the address. Treat juno.com addresses that could not be checked as unknown and confirm them with a real send or recent engagement.
Cleaning juno.com addresses you can't check
Treat inconclusive juno.com results as unknown, not bad. The checks that don't need the mailbox still work: format, typo domains, duplicates and whether the domain can receive mail. The free list health check runs those in the browser.
For the rest, use the address's history. An address that signed up, bought or replied recently is very likely live. For old or bought data at juno.com, send a small batch first and suppress anything that hard-bounces. If the juno.com share of your list is small, it's often simpler to keep those rows out of a high-risk campaign than to guess.
Common questions
- Can you verify @juno.com addresses?
- Partly. @juno.com often refuses checking servers before the mailbox question. The checker does probe @juno.com, but its server screens or defers unfamiliar checking connections. A refusal at that stage is about the connection, not the address, so it comes back risky ("Server refused our check" or "Mailbox check unavailable") and never invalid. It always checks the syntax, the domain's MX records, disposable domains and role addresses such as info@ first.
- Can I check if a juno.com address exists without emailing it?
- Usually not from a checking service. On 13 October 2026 Juno's server refused our checking connection at the greeting stage, before any mailbox question, so the result is inconclusive rather than valid or invalid.
- What mail servers does juno.com use?
- On 13 October 2026, juno.com published these MX hosts: mx.dca.untd.com, mx.vgs.untd.com. You can look them up yourself with the free MX lookup tool.
- Should I delete juno.com addresses that come back risky?
- No. For juno.com, risky reflects how the server treats checks, not the address. Remove the ones that fail format, typo-domain and duplicate checks, then send to the rest in a small batch and suppress whatever hard-bounces.
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