Domain reputation
Domain reputation is the trust score mailbox providers assign to your sending domain based on its authentication, sending history, engagement and complaint signals. Unlike IP reputation, it follows the domain wherever it sends, which is why it has become the dominant reputation signal as senders share pooled IPs.
How it works
Providers track how recipients treat mail from your domain — opens, replies, spam complaints, deletions without reading — plus authentication (SPF, DKIM, DMARC) and volume consistency. Positive engagement builds the score slowly; spikes, complaints and spam-trap hits erode it fast.
Why it matters
Because domain reputation travels with the domain, damage on one mailbox or subdomain can affect your whole domain's mail. Many teams send cold outreach from separate sending domains to protect their primary brand domain if reputation is harmed.
How do you choose and set up a separate outreach domain?
Pick a name a prospect would recognise as yours, such as a short prefix or suffix on the brand, and avoid strings of hyphens or keywords that look disposable. Point its website at your main site so anyone who types it in lands somewhere real. Then give it full SPF, DKIM and DMARC before a single message goes out, because a new domain starts with no history and missing authentication makes that worse.
Mailboxes on the new domain still need warming. The walkthrough on setting up a cold email domain covers DNS order and redirects. Check each record with a lookup after publishing, since a typo in a new domain's DNS is easy to miss when nothing has been sent yet.
Registration age matters less than behaviour, but a domain that sends cold volume in its first week gives receivers nothing to judge except that volume. Set it up a few weeks before you need it and let the warmup run while the rest of the campaign is prepared.
Does sending from a subdomain protect the main domain?
Partly. A subdomain such as outreach.yourbrand.com builds its own history, but receivers can and do relate subdomains to the organisational domain above them, so serious damage on the subdomain may still reach the parent. A separately registered domain gives cleaner isolation. The trade-off is recognition: a subdomain of the real brand looks more familiar to a prospect than a new domain they have never seen.
Whichever you choose, keep transactional mail such as password resets and invoices on the main domain and cold outreach elsewhere. Those receipts and resets matter far more to the business than any single campaign, and they should never share a reputation with experimental sending. If you ever retire an outreach domain, leave its DNS records and website redirect in place for a while so replies to old threads still reach you.
How do links and tracking domains affect domain reputation?
Filters score every domain that appears in a message, including the ones in links and images as well as the one in the From line. A link to a site with a poor history pulls the message down, and so does a click-tracking domain shared by many unrelated senders, because you inherit whatever they did with it. Using a custom tracking domain on your own DNS, or turning click tracking off for first-touch emails, removes that borrowed history.
Link shorteners are a special case of the same issue. Their domains carry the reputation of every sender who has used them, so a full link to your own site is usually safer. If you must shorten, use a branded short domain that only your team sends.
How many sending domains should a program run?
Work backward from mailboxes. Hypothetically, a program that needs 30 warmed mailboxes and chooses to put 3 on each domain runs 10 domains, and losing one pauses a tenth of the capacity. More domains means more isolation but also more DNS to monitor and more renewals to track, and a forgotten record on one of them can fail quietly. Autocloz monitors authentication per connected domain and applies per-domain caps and rotation, which keeps each domain's sender reputation visible on its own.
How Autocloz handles it
Autocloz protects domain reputation with mailbox warmup, SPF/DKIM/DMARC monitoring, per-domain sending caps and rotation, and bounce/complaint tracking — so volume scales only as fast as the domain's reputation can safely support.
Free tools for this
No signup required — they run in your browser.
FAQ
What is the difference between domain and IP reputation?
IP reputation is tied to the sending IP address; domain reputation is tied to your domain and follows it across IPs. As shared and pooled IPs became common, providers weight domain reputation more heavily, so protecting the domain is now paramount.
Should I use a separate domain for cold outreach?
Many teams do. Sending cold volume from a dedicated sending domain (or subdomain) isolates reputation risk, so if outreach reputation is damaged it doesn't drag down your primary brand domain's transactional and corporate mail.
Related terms
Mailbox warmup is the practice of gradually increasing a new email account's sending volume while generating positive engagement (opens, replies, moving mail out of spam) so mailbox providers build trust in the sender before real campaigns ramp up.
Sender reputation is the trust score mailbox providers assign to your sending domain and IP based on how recipients react to your mail — opens, replies, spam complaints, bounces and spam-trap hits. A high reputation lands you in the inbox; a low one routes you to spam or blocks you.
Inbox placement rate (IPR) is the percentage of delivered emails that actually land in the primary inbox rather than the spam/junk folder or a tab like Promotions. Unlike 'delivered' (which only means accepted by the server), IPR measures whether a human is likely to see the message.
IP warmup is the process of gradually increasing sending volume from a new or dormant dedicated IP address while maintaining high engagement, so mailbox providers build trust in that IP before it sends full volume. Sending large volume from a cold IP triggers throttling or spam-foldering because providers have no history to trust.