SMTP
521 Host Does Not Accept Mail 응답 모의 테스트
The host does not accept mail at all. This indicates the server exists but is explicitly configured to reject all incoming email messages.
전체 레퍼런스 보기 →1 HTTP 응답
HTTP/1.1 521 Host Does Not Accept Mail
Content-Type: application/json
Date: Tue, 25 Feb 2026 12:00:00 GMT
Content-Length: 65
{
"error": "server_error",
"message": "Host Does Not Accept Mail"
}
2 curl로 테스트하기
curl -i https://httpbin.org/status/521
3 프레임워크에서 521 Host Does Not Accept Mail 반환하기
django
from django.http import JsonResponse
def my_view(request):
return JsonResponse(
{"error": "server_error", "message": "Host Does Not Accept Mail"},
status=521,
)
flask
from flask import Flask, jsonify
app = Flask(__name__)
@app.route("/endpoint")
def my_endpoint():
return jsonify({"error": "server_error", "message": "Host Does Not Accept Mail"}), 521
fastapi
from fastapi import FastAPI
from fastapi.responses import JSONResponse
app = FastAPI()
@app.get("/endpoint")
def my_endpoint():
return JSONResponse(
content={"error": "server_error", "message": "Host Does Not Accept Mail"},
status_code=521,
)
express.js
// Express.js
app.get('/endpoint', (req, res) => {
res.status(521).json({"error": "server_error", "message": "Host Does Not Accept Mail"});
});
spring boot
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import java.util.Map;
@RestController
public class MyController {
@GetMapping("/endpoint")
public ResponseEntity<Map<String, Object>> myEndpoint() {
return ResponseEntity
.status(521)
.body(Map.of("error", "host_does_not_accept_mail",
"message", "Host Does Not Accept Mail"));
}
}
go net/http
package main
import (
"encoding/json"
"net/http"
)
func myHandler(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(521)
json.NewEncoder(w).Encode(map[string]string{
"error": "host_does_not_accept_mail",
"message": "Host Does Not Accept Mail",
})
}
ruby on rails
class MyController < ApplicationController
def my_action
render json: {"error": "server_error", "message": "Host Does Not Accept Mail"},
status: :host_does_not_accept_mail
end
end
asp.net core
// ASP.NET Core Minimal API
app.MapGet("/endpoint", () =>
Results.Json(
new { error = "host_does_not_accept_mail", message = "Host Does Not Accept Mail" },
statusCode: 521
)
);