1 on page 530) from any other machine anywhere
on the network. The SMTP showq command allows outsiders to view the contents of
the mail queue.
This is the Title of the Book, eMatter Edition
Copyright ?© 2007 O??™Reilly & Associates, Inc. All rights reserved.
158 | Chapter 4: Maintain Security with sendmail
If SMTPDEBUG (?§3.4.58 on page 144) is defined when sendmail is compiled, the
SMTP debug and showq commands are allowed to work; otherwise, they are disabled.
SMTPDEBUG should be defined only when modifying the sendmail code and
testing a new version. It should never be defined in an official release of sendmail. To
see whether it has been defined at your site, run the following command:
% telnet localhost 25
Trying 123.45.6.7 ...
Connected to localhost.
Escape character is '^]'.
220 localhost sendmail 8.12 ready at Fri, 13 Dec 2002 06:36:12 -0800
debug
500 Command unrecognized
quit
221 localhost.us.edu closing connection
Connection closed by foreign host.
%
When connected, enter the command debug. If you get the answer 500 Command
unrecognized, you know that SMTPDEBUG is not enabled. If, on the other hand,
you get the answer 200 Debug set, SMTPDEBUG is defined on your system, and you
should immediately take steps to correct the situation. Either contact your vendor
and request a new version of sendmail, or get the sendmail source and compile it with
SMTPDEBUG undefined.
Pages:
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308