Solution to the failure of sending emails using the linuxmail command

Use the built-in mail function in linux to test the mail sending function as follows: $ mail-stestxxx @ 163 comsldkfjlskdjf [CTRL & amp; 43; D] cc: sometimes a prompt is displayed: youhaveanewmailinvarspoolmailroot and cannot see emails in the mailbox. use the mail function provided by linux to test the Mail sending function as follows:
$ Mail-s test xxx@163.com
Sldkfjlskdjf [CTRL + D]
Cc:

Sometimes the following message is displayed:
You have a new mail in/var/spool/mail/root
And the email cannot be seen in the mailbox;

Solution:

1. View error logs
$ Tail-n 50/var/spool/mail/root

From MAILER-DAEMON @ ltv_73 Thu Dec 12 11:35:28 2013
Return-Path:
Received: from localhost (localhost)
By ltv_73 (8.13.8/8.13.8) id rBC3ZSPe006446;
Thu, 12 Dec 2013 11:35:28 + 0800
Date: Thu, 12 Dec 2013 11:35:28 + 0800
From: Mail Delivery Subsystem
Message-Id: <201312120335. rBC3ZSPe006446 @ ltv_73>
To:
MIME-type: 1.0
Content-Type: multipart/report; report-type = delivery-status;
Boundary = "rBC3ZSPe006446.1386819328/ltv_73"
Subject: Returned mail: see transcript for details
Auto-Submitted: auto-generated (failure)
This is a MIME-encapsulated message

-- RBC3ZSPe006446.1386819328/ltv_73

The original message was received at Thu, 12 Dec 2013 11:35:18 + 0800
From 41_154 [127.0.0.1]

----- The following addresses had permanent fatal errors -----

(Reason: 530 5.7.1 Client was not authenticated)

----- Transcript of session follows -----
... While talking to mail.163.com .:
>>> MAIL From: SIZE = 519
<530 5.7.1 Client was not authenticated
554 5.0.0 Service unavailable

-- RBC3ZSPe006446.1386819328/ltv_73
Content-Type: message/delivery-status

Reporting-MTA: dns; ltv_73
Received-From-MTA: DNS; sohu_41_154
Arrival-Date: Thu, 12 Dec 2013 11:35:18 + 0800

Final-Recipient: RFC822; xxx@163.com
Action: failed
Status: 5.7.1
Diagnostic-Code: SMTP; 530 5.7.1 Client was not authenticated
Last-Attempt-Date: Thu, 12 Dec 2013 11:35:28 + 0800

2. modify DNS
$ Vim/etc/resolv. conf
Change to an available DNS. the changes in this region take effect immediately after they are saved;

3. modify the host name [do not do this step]
$ Sysctl kernel. hostname = newhostname

4. restart the email service.
$ Service sendmail restart