Mailbox provider · Sina Mail
How to verify a sina.com email address
Can you verify @sina.com addresses?
YesYes. @sina.com answers mailbox checks one address at a time.
Check one address
Five checks a minute, no account needed. Nothing is sent to the address — we ask its mail server whether the mailbox exists, then disconnect.
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The checker opens an SMTP conversation with sina.com's mail server, offers a random address first to rule out a catch-all, then names your address at RCPT TO and disconnects without sending. A rejection comes back invalid ("Mailbox not found") and an acceptance valid ("Mailbox exists"). Temporary replies come back risky. It always checks the syntax, the domain's MX records, disposable domains and role addresses such as info@ first.
Mailbox existsMailbox not foundServer would not confirmSina Mail addresses can be verified without sending an email. On 13 October 2026 the sina.com mail server freemx1.sinamail.sina.com.cn rejected a made-up recipient at the SMTP RCPT TO step with 554 User no found., so a mailbox check can tell a missing sina.com account from a real one.
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Live DNS snapshot: sina.com
Checked 6 November 2026, 11:12 UTCRead from DNS at the time shown and refreshed at most once a day. MX says where mail for sina.com goes; SPF and DMARC describe mail sent from it, not whether any one address exists.
- 10
freemx2.sinamail.sina.com.cn - 10
freemx1.sinamail.sina.com.cn - 10
freemx3.sinamail.sina.com.cn
v=spf1 include:spf.sinamail.sina.com.cn -allp=none: meets the requirement, but blocks nothing. No rua= address, so you get no aggregate reports.
v=DMARC1; p=none;Look up any other domain with the MX lookup or the email provider lookup.
Sina Mail at a glance
| Operated by | Beijing SINA Internet Information Service Co., Ltd. (北京新浪互联信息服务有限公司), ChinaSource: Sina Mail terms of service (Chinese) |
|---|---|
| MX hosts | freemx1.sinamail.sina.com.cn, freemx2.sinamail.sina.com.cn, freemx3.sinamail.sina.com.cnObserved 13 October 2026 (dig MX) |
| Answer to a made-up address | 554 User no found., returned at RCPT TOObserved 13 October 2026 (SMTP probe of a made-up recipient, no message sent) |
| Address rule | Free Sina Mail addresses use the suffixes sina.com, sina.cn, 2008.sina.com and 51uc.com; paid VIP mail uses vip.sina.comSource: Sina Mail terms, clause 1.2 (Chinese) |
| Address rule | A mailbox registered with a mobile number gets two addresses on sina.cn, a number alias and a main account; changing the number retires the old aliasSource: Sina Mail terms, clauses 3.1.3 and 4.7 (Chinese) |
| Inactive accounts | A free Sina Mail account not used in any way (web, POP3, IMAP or app) for 90 consecutive days can be frozen or terminated; if it isn't unfrozen in the notice period the account is reclaimed and all its data deleted without recoverySource: Sina Mail terms, clause 4.6 (Chinese) |
What Sina Mail's server says about a missing mailbox
The reply that matters is the one to RCPT TO, the step where the checking server names the recipient. Sina Mail answered our made-up sina.com address with 554 User no found.. A 5xx code at that step is a permanent "no such mailbox", which is the same answer a real message would get, so SimpleVerifier marks the address invalid with the reason "Mailbox not found". A 250 at the same step means the mailbox exists and comes back valid.
Before trusting a "valid", a careful verifier also offers a random address that cannot exist. Sina Mail rejected ours, so sina.com is not a catch-all: a 250 for your address is a real signal. Temporary 4xx replies (421, 450, 451) are about the connection, not the mailbox, and come back risky with "Server would not confirm" rather than invalid. Hard bounce vs soft bounce explains why that split matters.
Sina answers with 554 and the text "User no found." at RCPT TO: a permanent rejection of that mailbox, unusual wording aside.
Sina Mail reclaims accounts unused for 90 days
Sina's terms (clause 4.6) let it freeze or terminate a free account that has had no web, POP3, IMAP or app use for 90 consecutive days. If the owner doesn't unfreeze it within the notice period, Sina reclaims the account and deletes the mail and contacts, with no way to restore them.
Clause 1.2 lists sina.com and sina.cn as free suffixes, and phone-number sign-ups get an alias that is retired if the number changes. A sina.com address that hasn't engaged for a quarter may be frozen, so remove permanent bounces and re-confirm quiet contacts before a large send.
Cleaning sina.com addresses on a list
Because Sina Mail answers honestly, sina.com is one of the domains where verification removes bounces before they happen. Drop the invalid results, keep the valid ones, and re-check the risky ones later: a temporary reply on one day often turns into a clear answer the next.
A valid result only means the mailbox exists today. Addresses on an old consumer list go stale as people stop using them, so re-verify before each large send to an aged segment; how often to verify an email list gives a schedule. Upload the CSV to the verifier and download the valid, risky and invalid rows as separate files.
Common questions
- Can you verify @sina.com addresses?
- Yes. @sina.com answers mailbox checks one address at a time. The checker opens an SMTP conversation with sina.com's mail server, offers a random address first to rule out a catch-all, then names your address at RCPT TO and disconnects without sending. A rejection comes back invalid ("Mailbox not found") and an acceptance valid ("Mailbox exists"). Temporary replies come back risky. It always checks the syntax, the domain's MX records, disposable domains and role addresses such as info@ first.
- Can I check if a sina.com address exists without emailing it?
- Yes. A verifier connects to Sina Mail's mail server, names the address at the RCPT TO step and disconnects before sending. On 13 October 2026 the server rejected a made-up sina.com address with "554 User no found.", so a missing mailbox shows up as invalid and the owner receives nothing.
- What mail servers does sina.com use?
- On 13 October 2026, sina.com published these MX hosts: freemx1.sinamail.sina.com.cn, freemx2.sinamail.sina.com.cn, freemx3.sinamail.sina.com.cn. You can look them up yourself with the free MX lookup tool.
- Why did a sina.com address come back risky instead of invalid?
- Risky means the server didn't give a permanent answer during the check, usually a temporary 4xx reply or a timeout. It isn't proof the address is bad. Check it again later; Sina Mail gave a clear rejection for a missing mailbox when we tested it.
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