sendmail遇到 Transient parse error -- message queued for future delivery的解决办法!

mail发送邮件问题解决
在服务的机器上，增加监控，要给自己发送邮件，邮件怎么也发送不出来。

进行检查： 用mail -v [e-mail] 进行检查：

用 sendmail -q -v 可以看到 Name server timeout
Transient parse error -- message queued for future delivery

# mail -v [e-mail]
Subject: test
test
Cc:
XXX.com: Name server timeout
[e-mail]... Transient parse error -- message queued for future delivery
[e-mail]... queued

查看mail log： /var/log/maillog
Dec 28 15:33:05 testmachine sendmail[19124]: nBS7X4Qn019124: from=root, size=44, class=0, nrcpts=1, msgid=<[e-mail]>, relay=root@localhost
Dec 28 15:33:05 newlido363 sendmail[19124]: nBS7X4Qn019124: to=[e-mail], delay=00:00:01, mailer=esmtp, pri=30044, dsn=4.4.3, stat=queued

在 /var/spool/clientmqueue/目录中，多了个未发送邮件
#ls
dfnBS7aN0W019327
qfnBS7aN0W019327

# cat qfnBS7aN0W019327
V8
T1261985783
K1261985784
N1
P30044
Mhost map: lookup (XXX.com): deferred
Fbs
$_root@localhost
${daemon_flags}c u
Sroot
[e-mail]
rRFC822; [e-mail]
RPFD:[e-mail]
H?P?Return-Path:
H??Received: (from root@localhost)
        by localhost.localdomain (8.13.1/8.13.1/Submit) id nBS7aN0W019327
        for [e-mail]; Mon, 28 Dec 2009 15:36:23 0800
H?D?Date: Mon, 28 Dec 2009 15:36:23 0800
H?F?From: root
H?x?Full-Name: root
H?M?Message-Id: <[e-mail]>
H??To: [e-mail]
H??Subject: test
.

（要求：本机不配置ＤＮＳ，也应该能够发送邮件）
------------
查资料：
1. DNS配的问题：
  在/etc/hosts中加入了 mail.XXX.com的解析。
  在/etc/host.conf中，检查了先hosts，再resolve
  还是无用

2. 查资料：
　　上面写着有一个文件：/etc/mail/service.switch，原文贴出来：
问题解决了，果然就是service.switch的问题！

这个邮件发不出去的linux主机上没有这个文件，sendmail.cf里有：
# service switch file (name hardwired on Solaris, Ultrix, OSF/1, others)
#O ServiceSwitchFile=/etc/mail/service.switch

我登陆另一台也是要求不能使用dns解析，但能够正常收发邮件的主机（HPUX机器）上查了一下，它的/etc/mail下有service.switch文件。

我截取了hpux上service.switch的一部分内容放到linux机器上新建的service.switch中：
引用：# This file contains the fallback mechanism used by sendmail
# when resolving hostnames and aliases. If this file does
# not exist, then the fallback is
#
#       hosts   dns nis files
#       aliases files nisplus nis
#
# The default fallback for this file is
#
#       hosts   dns files
#       aliases files
#
# Note that the format of entries in this file consists of the
# service name (either 'hosts' or 'aliases'), followed by white
# space or a tab, and the list of lookup sources as mentioned
# above (dns, nis, nisplus, files).
#
# If sendmail is running in a non-DNS and non-NIS environment, for
# example, the entry for hosts should be:
#
#hosts   files
#aliases files
#
# This means that hostnames will be resolved by referencing /etc/hosts
# and aliases will be resolved by referencing /etc/mail/aliases.
##

并把里面的
#hosts   files
#aliases files
的注释去掉：
hosts   files
aliases files

这样自己也修改一下，可以发送邮件了

另外还要注意 /etc/nsswitch.conf
hosts: files [NOTFOUND=return UNAVAIL=continue]
这个文件配置不当，也会出现 Transient parse error -- message queued for future delivery



－－－－－－－－－－－
说另一种方法：
Add "xxx.com"  keyword to /etc/mail/access and /etc/mail/local-host-names, then run "cd /etc/mail && make -C /etc/mail && /etc/init.d/sendmail restart" , and check it again.