DNS tools
Look up any record, validate DNSSEC, and watch propagation across resolvers.
See which certificate authorities are allowed to issue for your domain.
DNS lookupLook up A, AAAA, MX, TXT, NS, and CNAME records for any domain.
DNS propagation checkerCheck a DNS record across multiple public resolvers and spot mismatches.
DNSSEC checkerValidate your domain's chain of trust and spot broken signatures.
Nameserver lookupList a domain's NS records and check the delegation agrees.
Reverse DNS (PTR)Find the hostname an IP address points back to.
SOA record lookupRead a zone's serial, refresh, retry, and expiry timers.
Your DNS is the address book that points visitors and email to the right servers, and a single bad record can take a domain offline or silently break delivery. These free DNS tools let you look up every record type, validate your DNSSEC chain of trust, confirm your nameservers agree, and watch a change propagate across public resolvers. Run a one-off check any time — and when a record absolutely must not change without you knowing, SJ Monitor's DNS monitoring watches it around the clock and alerts you the moment it does.
Frequently asked questions
Which DNS records should I check regularly?
At minimum your A/AAAA, MX, NS, and any TXT records used for email (SPF/DKIM/DMARC). Unexpected changes to these are the most common cause of outages and delivery failures.
Can SJ Monitor alert me when a DNS record changes?
Yes. DNS monitoring snapshots your records and notifies you immediately if any of them change, which catches both mistakes and hijacks early.
Why has my DNS change not taken effect yet?
Resolvers cache records until their TTL expires, so a change can take minutes to hours to be seen everywhere. Lowering the TTL before a planned edit speeds this up; the propagation checker confirms when it's done.
What's the difference between a DNS lookup and DNS monitoring?
A lookup is a one-off snapshot you run by hand; monitoring re-checks the same records continuously and alerts you the moment one changes, so a silent edit or hijack never goes unnoticed.
Do I need DNSSEC?
DNSSEC signs your records so resolvers can detect forgery, which is valuable for high-trust domains. It adds operational care — expired signatures can take a domain offline — so weigh the protection against the maintenance, and monitor the chain if you enable it.
Other tool categories
Want any of this watched around the clock? Turn on SJ Monitor's DNS monitoring — create a free account and we'll alert you the moment something changes.