Halkali merkez neighborhood fatih st ozgur apt no 46 , Kucukcekmece , Istanbul , 34303 , TR
If business email lands in spam, never arrives or bounces with SMTP errors, the cause may be authentication, reputation, reverse DNS, TLS, alignment, sending behavior or SMTP infrastructure. We separate these layers before recommending changes.
Do not send mailbox or hosting passwords for the first review. Send the domain, affected provider, full bounce text and preferably the raw header of a test message.
SPF, DKIM, DMARC, PTR and SMTP reputation
Authentication is not an inbox guarantee. IP/domain reputation, complaints, bounce rate, sudden volume, list quality, linked domains and recipient engagement also affect filtering.
Domain adına hangi kaynakların mail göndermeye yetkili olduğunu belirtir.
Turkey (Turkish)
Germany (German)
Worldwide (English)
v=spf1 ip4:203.0.113.25 include:_spf.ornekservis.com -allMesajı dijital imza ile doğrular.
selector1._domainkey.example.com → v=DKIM1; k=rsa; p=PUBLIC_KEYSPF/DKIM sonuçlarını From domainiyle hizalar ve policy/raporlama sağlar.
_dmarc.example.com → v=DMARC1; p=none; rua=mailto:[email protected]Gönderici IP'yi geriye doğru hostname'e çözer.
203.0.113.25 → mail.example.comDomain'e gelen maili hangi sunucunun kabul edeceğini tanımlar.
example.com → 10 mail.example.comSMTP aktarımını şifreler.
STARTTLS / TLS 1.2+| Error / Status | Where | Likely meaning | First check |
|---|---|---|---|
| 550 5.7.26 | Gmail | Gönderici authentication yetersiz veya başarısız olabilir. | Header içindeki spf=, dkim=, dmarc= ve alignment kontrol edilir. |
| 550 5.7.515 | Outlook / Hotmail | Gönderici domain gereken authentication seviyesini karşılamıyor. | SPF, DKIM, DMARC ve From/MailFrom/DKIM alignment incelenir. |
| 421 4.7.0 | Gmail / çeşitli | Geçici rate limit, PTR veya reputation sorunu olabilir. | PTR, forward DNS, gönderim hızı ve tam hata metni incelenir. |
| 451 / 4.x.x | Çeşitli | Geçici SMTP hata sınıfı; greylist/rate limit/DNS olabilir. | Queue retry ve enhanced status code değerlendirilir. |
| 550 5.1.1 | Çeşitli | Alıcı adresi yok veya geçersiz. | Liste hijyeni ve alıcı adresi doğrulanır. |
| SPF PermError | Authentication | SPF syntax, çoklu kayıt veya 10 lookup sınırı. | SPF ağacı include/redirect dahil çözülür. |
| DKIM Fail | Authentication | Selector/key/imza problemi. | DKIM-Signature d=/s= ve Authentication-Results kontrol edilir. |
| DMARC Fail | Authentication | Aligned SPF veya DKIM pass yok. | From, smtp.mailfrom ve DKIM d= domainleri karşılaştırılır. |
| Spam klasörü | Gmail/Outlook/Yahoo | Authentication geçse bile reputation/complaint/engagement zayıf olabilir. | Postmaster, bounce, complaint ve gönderim davranışı değerlendirilir. |
SPF, DKIM and DMARC verify identity, while inbox placement also considers reputation, complaints, bounces, engagement and sending history. A perfect authentication result is a foundation rather than a guarantee.
Read the receiving provider result and raw header before changing DNS records.
SPF authorizes sources for the 5321.MailFrom domain. Publish one valid SPF policy and keep DNS-querying mechanisms within the RFC 7208 limit of 10.
SPF pass alone does not guarantee DMARC because alignment still matters.
A DNS DKIM key is useful only if the outbound system actually signs mail. Inspect d=, s= and dkim=pass/fail in the raw header.
Wrong selectors, stale keys or message modification can produce failures.
DMARC needs an aligned SPF or DKIM pass for the visible From domain. Use p=none to inventory legitimate senders before enforcing quarantine or reject.
Do not move to reject until CRM, billing, web apps and marketing platforms are correctly authenticated.
SPF can pass on a service domain but still fail DMARC alignment. DKIM can also pass with a non-aligned d= signing domain.
Custom return-path and custom DKIM are important for third-party services.
Major providers expect valid forward and reverse DNS for sending IPs. PTR is normally controlled by the IP provider, not a standard DNS TXT record.
Forward-confirmed reverse DNS is a healthy pattern for self-hosted SMTP.
The sending server should identify with a resolvable FQDN rather than localhost or an invalid local name.
HELO/EHLO, PTR and A records should be reasonably consistent on self-hosted mail.
Modern providers expect secure SMTP transport. STARTTLS, a healthy certificate chain and current protocol support matter.
Ports 25, 465 and 587 serve different SMTP roles.
Google requires SPF or DKIM for all senders plus forward/reverse DNS and TLS; qualifying bulk senders need SPF, DKIM, DMARC, alignment and one-click unsubscribe for marketing/subscription messages.
Google instructs senders to keep Postmaster Tools spam rate below 0.3%.
550 5.7.515 indicates the visible From domain does not meet Microsoft authentication requirements for the sender classification.
Review SPF, DKIM, DMARC and third-party sender alignment together.
Yahoo expects authentication and low complaint rates; bulk senders should use SPF, DKIM and DMARC with good list hygiene.
An inbox result at Gmail does not guarantee the same result at Yahoo or Outlook.
Authentication proves identity; reputation reflects historical trust. Dedicated IP is not automatically better than a well-managed shared pool.
Volume, list quality and history must be considered before changing IPs.
A public blocklist listing is a signal, not the only filtering input. Fix the spam source before requesting delisting.
On shared hosting the provider's outbound pool may be the real source of reputation problems.
Use your own authenticated domain in From and put the visitor address in Reply-To. SMTP plugins help but do not replace correct DNS and reputation.
Do not use the visitor's Gmail address as your From header.
PHP mail() uses the local MTA; authenticated SMTP/API provides more control and logging. Third-party services still need custom domain authentication.
Choose architecture based on transactional/marketing traffic, volume and log requirements.
Sudden high volume, old lists, hard bounces and complaints can quickly damage reputation. Permission and list hygiene are essential.
Separating transactional and marketing streams can help protect critical message reputation.
Gmail requires RFC-style one-click unsubscribe for qualifying bulk marketing/subscription traffic. Transactional mail is a different category.
Easy unsubscribe reduces complaints and supports provider requirements.
Authentication-Results, Return-Path, From, DKIM d=/s= and Received lines are the core fields for diagnosis.
A full raw header is more valuable than one authentication screenshot.
Public testers are useful hygiene tools but cannot reproduce every private reputation and engagement signal used by mailbox providers.
Use score improvements as diagnostics, not as inbox guarantees.
A website, CRM, billing system and newsletter can all send under one domain with different authentication behavior. Inventory every sender.
DMARC reports help discover unknown or forgotten senders.
TTL and resolver caches can delay DNS visibility, while reputation does not reset when a TXT record changes.
After propagation, send a fresh message and inspect the new header.
Send the domain, provider, bounce text and raw header. Public DNS/authentication checks come first; server logs and queues are scoped only when needed.
Passwords are not needed for the first step.
Do not copy these blindly; values must match your real infrastructure.
v=spf1 ip4:203.0.113.25 -allv=spf1 ip4:203.0.113.25 include:_spf.ornekservis.com -allv=DMARC1; p=none; rua=mailto:[email protected]; adkim=r; aspf=rv=DMARC1; p=quarantine; pct=100; rua=mailto:[email protected]v=DMARC1; p=reject; pct=100; rua=mailto:[email protected]List-Unsubscribe-Post: List-Unsubscribe=One-Click
List-Unsubscribe: <https://example.com/unsubscribe/token>Your hosting or software does not need to have been purchased from us.
SPF, DKIM, PTR, HELO, queue, mail log ve outbound IP
Domain authentication, outbound control ve DNS
SPF/DKIM/DMARC, Postmaster ve third-party sender
SPF/DKIM/DMARC, Exchange Online ve alignment
Form, sipariş, üyelik ve SMTP eklentisi
SMTP/API, queue, Return-Path ve From/Reply-To
Bulk authentication, unsubscribe ve reputation
PTR, hostname, TLS, queue ve HELO/EHLO
Spam klasörü mü, bounce mı, gecikme mi?
Web site, mailbox, CRM veya newsletter hangisi gönderiyor?
SPF, DKIM, DMARC, Return-Path, From, d= ve IP çıkar.
SPF, DKIM, DMARC, MX, A/AAAA ve PTR kontrol et.
HELO/EHLO, hostname ve TLS kontrol et.
IP/domain, shared IP, complaint ve bounce ayrımı yap.
Hacim, liste, unsubscribe ve marketing/transactional ayrımı.
Yeni mail header ve alıcı sonucu ile doğrula.
Send the domain, affected mailbox provider, full error and preferably a raw header. Passwords are not required for the initial analysis.
Yes. Reputation, complaints, engagement, list quality and content still affect filtering.
The SPF-authenticated MailFrom domain may not align with the visible From domain.
Yes, if the DKIM signing domain is not aligned with the visible From domain.
Publish one valid SPF policy and merge legitimate sources into it.
RFC 7208 limits DNS-querying SPF terms to 10 during evaluation.
Normally no; reverse DNS is controlled by the IP range provider.
No. Provider reputation and engagement signals are not fully reproduced by public testers.
Providers use different policies and reputation systems; Outlook also has provider-specific authentication errors.
It commonly indicates insufficient sender authentication; inspect SPF, DKIM, DMARC and alignment.
The From domain does not meet the required authentication level for the sender classification.
Not by itself. DNS, alignment and reputation must also be correct.
No. Use your own authenticated domain as From and the visitor as Reply-To.
No. It needs reputation and careful volume growth.
A standards-based unsubscribe mechanism required for qualifying bulk marketing/subscription messages.
Yes, if malicious scripts send spam through the server or mailbox.
Domain, affected provider, complete bounce text and preferably the raw header; do not send passwords initially.
Send the domain, affected mailbox provider, full error and preferably a raw header. Passwords are not required for the initial analysis.