Solved

Host.Allow, Host.Deny

Posted on 2007-11-21
6
2,159 Views
Last Modified: 2013-12-17
I want to refuse a whole set of IP from all services except sending email to us.
eg. IP 89.
In the host.allow file :
sendmail: 89.

In the host.deny file:
ALL: 89.

Is this correct ?

0
Comment
Question by:ChanYiuPong
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
6 Comments
 
LVL 10

Expert Comment

by:ssvl
ID: 20332903
Yes you are right


order is this:

1. Allow the connection if it matches a line in hosts.allow. End.

2. Deny the connection if it maches a ling in hosts.deny. End.

3. Allow the connection.

Since the default is to allow any connection that doesn't match,
0
 

Author Comment

by:ChanYiuPong
ID: 20333429
But will the ALL override the sendmail. Do you mean that when it saw sendmail in host.allow with the IP, then it will not check host.deny ?
0
 

Author Comment

by:ChanYiuPong
ID: 20333441
And I should use "sendmail" and not "email" or something like that ?
0
Don't Cry: How Liquid Web is Ensuring Security

WannaCry is just the start. Read how Liquid Web is protecting itself and its customers against new threats.

 
LVL 3

Expert Comment

by:amirs80
ID: 20333541
--------/etc/hosts.allow--------
ALL : attack_ip : DENY
sendmail : attack_ip : DENY
smtp : attack_ip : DENY

please check this
0
 
LVL 3

Expert Comment

by:mediaonegraphics
ID: 20338630
I agree with ssvl. The allow is parsed before deny. Also just put a sendmail allow and not smtp as it is handled by the sendmail daemon.
0
 
LVL 10

Accepted Solution

by:
ssvl earned 500 total points
ID: 20345982
But will the ALL override the sendmail. Do you mean that when it saw sendmail in host.allow with the IP, then it will not check host.deny

Yes(it check and reject the 2nd occurrence.)



And I should use "sendmail" and not "email" or something like that ?

You should use a service name

FYR
http://www.softpanorama.org/Net/xinetd_and_tcp_wrappers.shtml
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This process describes the steps required to Import and Export data from and to .pst files using Exchange 2010. We can use these steps to export data from a user to a .pst file, import data back to the same or a different user, or even import data t…
As tax season makes its return, so does the increase in cyber crime and tax refund phishing that comes with it
The basic steps you have just learned will be implemented in this video. The basic steps are shown to configure an Exchange DAG in a live working Exchange Server Environment and manage the same (Exchange Server 2010 Software is used in a Windows Ser…
Established in 1997, Technology Architects has become one of the most reputable technology solutions companies in the country. TA have been providing businesses with cost effective state-of-the-art solutions and unparalleled service that is designed…

717 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question