Question

我正在创建一个脚本来测试HELO的电子邮件..

直接在telnet控制台中，命令运行正常，但在脚本中，我无法获得输出。

在bash中：

$ telnet alt1.aspmx.l.google.com 25
HELO verify-email.org
MAIL FROM: <check@verify-email.org>
RCPT TO: <test@gmail.com>
quit

结果：

root@san [~]# telnet alt1.aspmx.l.google.com 25
Trying 2a00:1450:4010:c09::1a...
Connected to alt1.aspmx.l.google.com.
Escape character is '^]'.
220 mx.google.com ESMTP qm6si6508388lbb.110 - gsmtp
HELO verify-email.org
250 mx.google.com at your service
MAIL FROM: <check@verify-email.org>
250 2.1.0 OK qm6si6508388lbb.110 - gsmtp
RCPT TO: <test@gmail.com>
550-5.1.1 The email account that you tried to reach does not exist. Please try
550-5.1.1 double-checking the recipient's email address for typos or
550-5.1.1 unnecessary spaces. Learn more at
550 5.1.1  https://support.google.com/mail/answer/6596 qm6si6508388lbb.110 - gsmtp
quit
221 2.0.0 closing connection qm6si6508388lbb.110 - gsmtp
Connection closed by foreign host.

在剧本中：

cat << EOF | telnet alt1.aspmx.l.google.com 25
HELO verify-email.org
MAIL FROM: <check@verify-email.org>
RCPT TO: <test@gmail.com>
quit
EOF

OR

{ echo "HELO verify-email.org"; sleep 1; echo "MAIL FROM: <check@verify-email.org>"; sleep 1; echo "RCPT TO: <test@gmail.com>" ; sleep 1 ;  echo quit } | telnet alt1.aspmx.l.google.com 25

OR

#!/usr/bin/expect -f

spawn  alt1.aspmx.l.google.com 25
send '"HELO verify-email.org\r"'
send '"MAIL FROM: <check@verify-email.org>\r"'
send '"RCPT TO: <test@gmail.com>\r"'
send '"quit\r"'

OR

sh aa 1> aa.txt 2>&1

OR

sh aa &> aa.txt

没有结果。

Answer 1

通常，您可能不希望将内容管道传输到telnet。一个合理的替代方案是netcat（在大多数系统上都是nc。

那就是说，我前一段时间写了a tiny bash HTTP client，依靠bash的内部支持来建立TCP套接字连接。 SMTP客户端稍微复杂一些，但仍然相当容易。 SMTP很好。您可以加载一堆命令，然后只需一次读取多个响应行。

#!/usr/bin/env bash

target="$1"
address="$2"

success=""

# Open a two-way socket connection on fd/3
exec 3<>/dev/tcp/$target/25

# Stand back, we're doing SMTP!
printf "HELO $HOSTNAME\r\n" >&3
printf "MAIL FROM: <$USER@$HOSTNAME>\r\n" >&3
printf "RCPT TO: <$address>\r\n" >&3
printf "QUIT\r\n" >&3

# Now that we've had our say, it's time to listen.
while read -u 3 code message; do
  echo ">> <$code> ${message%$'\r'}"    # Debugging output
  case "$code" in
    2??) success="${success:-true}" ;;  # Only set variable if it's not already set
    5??) success=false ;;               # (i.e. false overrides all other responses)
  esac
done

# Close connections, clean up after ourselves
exec 3<&-; exec 3>&-

if [ -z "$success" ]; then
        echo "NOTICE: Not sure we reached an SMTP server..."
        exit 1
elif $success; then
        echo "NOTICE: All's well, $target accepts mail for $address"
else
        echo "NOTICE: I detected a failure."
        exit 1
fi

请注意${message%$'\r'}的参数扩展，如果它是CR，则会删除该行中的最后一个字符。这样做是因为SMTP响应使用\r\n作为换行符，而您的脚本可能认为\r仅仅是行的一部分（或$ message变量）。

使用shell脚本在日志中保存来自telnet的SMTP会话

1 个答案: