SMTP 220 Service Ready vs 250 OK
Both SMTP 220 (Service Ready) and 250 (OK) belong to the 2xx Positive Completion category. 220 indicates that the SMTP server is ready to begin the mail transaction. This greeting is the first response a client receives upon connecting, and it typically includes the server's hostname and software identificati Meanwhile, 250 means that the requested mail action has been completed successfully. This is the most common positive response in SMTP, returned after HELO/EHLO, MAIL FROM, RCPT TO, and DATA completion.
คำอธิบาย
The SMTP server is ready to begin the mail transaction. This greeting is the first response a client receives upon connecting, and it typically includes the server's hostname and software identification.
เมื่อคุณพบเห็น
Immediately after establishing a TCP connection to the mail server on port 25, 465, or 587. This is the server's welcome banner confirming it is ready to accept commands.
วิธีแก้ไข
No fix needed — this confirms a successful connection. If you do not receive this greeting, check that the server is running, the port is correct, and no firewall is blocking the connection.
คำอธิบาย
The requested mail action has been completed successfully. This is the most common positive response in SMTP, returned after HELO/EHLO, MAIL FROM, RCPT TO, and DATA completion.
เมื่อคุณพบเห็น
After nearly every successful SMTP command — greeting, specifying sender, adding recipients, or completing message delivery. This is the standard success confirmation.
วิธีแก้ไข
No fix needed — the command was accepted. If a command that should succeed returns a different code, check the command syntax and server policies.
ความแตกต่างหลัก
SMTP 220: The SMTP server is ready to begin the mail transaction. This greeting is the first response a client receives upon connecting, and it typically includes the server's hostname and software identificati
SMTP 250: The requested mail action has been completed successfully. This is the most common positive response in SMTP, returned after HELO/EHLO, MAIL FROM, RCPT TO, and DATA completion.
You encounter 220 when immediately after establishing a TCP connection to the mail server on port 25, 465, or 587. This is the server's welcome banner confirming it is ready to accept commands.
You encounter 250 when after nearly every successful SMTP command — greeting, specifying sender, adding recipients, or completing message delivery. This is the standard success confirmation.
ควรใช้อันไหนเมื่อไร
For 220 (Service Ready): No fix needed — this confirms a successful connection. If you do not receive this greeting, check that the server is running, the port is correct, and no firewall is blocking the connection. For 250 (OK): No fix needed — the command was accepted. If a command that should succeed returns a different code, check the command syntax and server policies.