Free deliverability tool
Before connecting SMTP relays, webhooks, or custom integrations, confirm the target host accepts traffic on the expected port. This port checker tests reachability so you can distinguish DNS issues from firewall or service outages.
Built for B2B teams, operators, and agencies who need clear DNS and deliverability signals — not buried technical noise.
Enter the hostname or IP and the port your service listens on.
See whether the port appears open and reachable from the checker environment.
If closed, review security groups, hosting firewalls, and service status.
Authentication fixes deliverability at the domain level. DevBoxy free email verifier helps you clean addresses before campaigns go out.
