Tools

Is this mail server's IP blocklisted, and is its reverse DNS set up the way receivers expect?

Is this domain's email set up correctly: MX, DMARC, DKIM and SPF?

Why did this message arrive late, land in spam, or fail authentication?

Is this IP address, or this whole range, allowed to send mail for the domain?

Who is this domain registered with, when does it expire, and is it locked?

Which nameservers are authoritative for this domain, and which DNS provider runs them?

What does DNS return for this name right now?

What does each public resolver return for this record right now?

Is this domain's DNS signed, and does the chain of trust validate?

Where does this CNAME chain end, and which record finally answers?

Can this domain and its mail servers be reached over IPv6?

Which public address does the internet see for me, and what does its reverse DNS say?

Who owns this IP address, and where do I report abuse from it?

Which hostname does this IP address claim, and does that name point back?

Which network announces this address block, and who is responsible for it?

Is this host reachable from around the world, and how far away is it?

Where does traffic to this host go, and which hop is slow?

Is this server's certificate valid, trusted and issued for the name I use?

Which security headers does this site send, and what is missing?

What are the network, the mask and the usable host range for this prefix?

How long will this transfer take, or how much traffic will this site use?