How to verify an earthlink.net email address

EarthLink's server replied 550 5.7.1 Connection refused - blocked by Validity - ELNK001_102. That refusal happened at the greeting stage, before the checking server could name any recipient, so it is a verdict on the connecting server, not on the address. SimpleVerifier returns these as risky with "Mailbox check unavailable" and never as invalid, because treating a refusal as "mailbox not found" would delete real customers from your list.

Servers screen connections this way to keep spam out: missing reverse DNS, a low sending reputation or a blocklist listing are the usual triggers. The same screen applies to every checking service that connects from a shared or new IP, which is why earthlink.net results differ between verifiers. SMTP verification false positives explains how much to trust each answer.

EarthLink's inbound mail is filtered by Vade (the earthlink-vadesecure.net hosts), and the refusal code ELNK001_102 is documented on EarthLink's Vade postmaster page as a blocklist rejection of the connecting IP.

Treat inconclusive earthlink.net results as unknown, not bad. The checks that don't need the mailbox still work: format, typo domains, duplicates and whether the domain can receive mail. The free list health check runs those in the browser.

For the rest, use the address's history. An address that signed up, bought or replied recently is very likely live. For old or bought data at earthlink.net, send a small batch first and suppress anything that hard-bounces. If the earthlink.net share of your list is small, it's often simpler to keep those rows out of a high-risk campaign than to guess.