DNS Lookup

Every record carries a TTL in seconds, and resolvers are allowed to cache the old answer for that long. With a TTL of 3600 you may see the previous value for up to an hour; at 86400, up to a day. This tool asks Cloudflare's public resolver directly, so authoritative changes usually show up here quickly, but your ISP's resolver and your own device cache can lag further behind. If you are planning a migration, lower the TTL to around 300 seconds a few days beforehand.

SPF is a TXT record beginning with v=spf1 that lists which servers may send mail using your domain in the envelope sender. DMARC lives on _dmarc.<domain> and says what receivers should do when SPF and DKIM both fail — p=none only monitors, quarantine sends to spam, reject refuses the message — and where to send aggregate reports. SPF alone carries no enforcement, so publishing both is the usual baseline.

By design, a name that has a CNAME cannot carry any other record type. A CNAME says "this name is just an alias, go look over there", and DNS delegates everything else to the target. That is why you cannot put a CNAME on the apex of a domain (example.com itself) — it would collide with the mandatory NS and any MX records. To point an apex at another host, use your provider's ALIAS, ANAME or CNAME-flattening feature instead.

It is the preference value, and lower wins. With a 10 and a 20, mail normally goes to the host listed at 10 and only falls back to 20 when the first does not answer. Several hosts sharing the same number split the load between them. The absolute values carry no meaning — only their relative order — so people conventionally use round numbers like 10, 20 and 30 to leave room for inserting servers later.