net/smtp: SendMail blocked at smtp.Client.StartTLS

hiroyukki commented 3 weeks ago

Go version

go version go1.20.13 windows/386

Output of `go env` in your module/workspace:

set GO111MODULE=
set GOARCH=386
set GOBIN=
set GOCACHE=C:\Users\jiayi\AppData\Local\go-build
set GOENV=C:\Users\jiayi\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=
set GOFLAGS=
set GOHOSTARCH=386
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=D:\gopath\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=D:\gopath
set GOPRIVATE=
set GOPROXY=https://goproxy.io
set GOROOT=D:\Programs\go
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=D:\Programs\go\pkg\tool\windows_386
set GOVCS=
set GOVERSION=go1.20.13
set GCCGO=gccgo
set GO386=sse2
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=E:\libgx\go\go.mod
set GOWORK=
set CGO_CFLAGS=-O2 -g
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-O2 -g
set CGO_FFLAGS=-O2 -g
set CGO_LDFLAGS=-O2 -g
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m32 -mthreads -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=C:\Users\jiayi\AppData\Local\Temp\go-build1503534736=/tmp/go-build -gno-record-gcc-switches

What did you do?

I send mail with net/smtp, some smtp server seems incompatible, my code:

func main() { from := "test@gooxion.com" to := []string{"test2@gooxion.com"} auth := smtp.PlainAuth("", from, "wrong_pswd", "smtp.exmail.qq.com:25") fmt.Println("pre sendMail") fmt.Println(smtp.SendMail("smtp.exmail.qq.com:25", auth, from, to, []byte("hello"))) fmt.Println("post sendMail") }

What did you see happen?

smtp.SendMail blocked (at smtp.Client.StartTLS) for about 2 minutes, until socket timeout

What did you expect to see?

STMP protocol can be run normally, failed or succeeded faithfully but not hang

mknyszek commented 3 weeks ago

This may be a long-shot but CC @bradfitz via https://dev.golang.org/owners. Maybe also CC @neild? Not sure.

gabyhelp commented 3 weeks ago

Similar Issues

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rsc commented 2 days ago

This program works fine for me (prints StartTLS worked) using a cloud system that can dial port 25 (my home internet gets blocked by my ISP):

package main

import (
    "crypto/tls"
    "log"
    "net/smtp"
)

func main() {
    addr := "smtp.exmail.qq.com:25"
    println("dial...")
    c, err := smtp.Dial(addr)
    if err != nil {
        log.Fatal(err)
    }
    defer c.Close()
    println("extensions?...")
    if ok, _ := c.Extension("STARTTLS"); ok {
        println("starttls...")
        config := &tls.Config{ServerName: "smtp.exmail.qq.com"}
        if err = c.StartTLS(config); err != nil {
            log.Fatal(err)
        }
        log.Fatal("StartTLS worked")
    }
    log.Fatalf("no tls")
}

Does it work for you?

golang / go