The Community Forums

Interact with an entire community of cPanel & WHM users!
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Block local relay without authentication

Discussion in 'E-mail Discussions' started by brandon45, Jun 29, 2015.

  1. brandon45

    brandon45 Member

    Joined:
    May 26, 2014
    Messages:
    7
    Likes Received:
    0
    Trophy Points:
    1
    cPanel Access Level:
    Root Administrator
    I've noticed that I can send mail from any existing user to any other existing user on the server without authentication, for example if I have two domains hosted on whm domainone.com and domaintwo.com I can send mails from mail@domainone.com to mai@domaintwo.com or even to himself without the need to authenticate
    is there an exim acl that I can use to block it(I don't want to enforce spf)?
     
    #1 brandon45, Jun 29, 2015
  2. storminternet

    storminternet Well-Known Member

    Joined:
    Nov 2, 2011
    Messages:
    462
    Likes Received:
    0
    Trophy Points:
    16
    cPanel Access Level:
    Root Administrator
    Are you using any script or application to send emails from one domain to another or using outlook ?
     
    #2 storminternet, Jun 29, 2015
  3. brandon45

    brandon45 Member

    Joined:
    May 26, 2014
    Messages:
    7
    Likes Received:
    0
    Trophy Points:
    1
    cPanel Access Level:
    Root Administrator
    I'm not, I want to block it because I'm receiving spam messages from for example mail@mydomain.com to mail@mydomain.com
     
    #3 brandon45, Jun 29, 2015
  4. cPanelMichael

    cPanelMichael Forums Analyst
    Staff Member

    Joined:
    Apr 11, 2011
    Messages:
    34,852
    Likes Received:
    1,062
    Trophy Points:
    113
    cPanel Access Level:
    Root Administrator
    Hello :)

    How are you sending the email without authentication (e.g. email client, script)? Are you sure that you are not just spoofing the "FROM" address? Have you reviewed the message header to see if it shows the actual sender address?

    Thank you.
     
    #4 cPanelMichael, Jul 20, 2015
  5. brandon45

    brandon45 Member

    Joined:
    May 26, 2014
    Messages:
    7
    Likes Received:
    0
    Trophy Points:
    1
    cPanel Access Level:
    Root Administrator
    I'm using telnet, for example

    Code:
    ehlo test.local
mail from:<account@mydomain.com>
rcpt to:<account@mydomain.com>
data
.
     
    #5 brandon45, Jul 20, 2015
  6. cPanelMichael

    cPanelMichael Forums Analyst
    Staff Member

    Joined:
    Apr 11, 2011
    Messages:
    34,852
    Likes Received:
    1,062
    Trophy Points:
    113
    cPanel Access Level:
    Root Administrator
    What shows up in the message header for the sender?

    Thank you.
     
    #6 cPanelMichael, Jul 21, 2015
  7. brandon45

    brandon45 Member

    Joined:
    May 26, 2014
    Messages:
    7
    Likes Received:
    0
    Trophy Points:
    1
    cPanel Access Level:
    Root Administrator
    Code:
    Return-path: <account@mydomain.com>
Envelope-to: account@mydomain.com
Delivery-date: Mon, 20 Jul 2015 18:53:55 +0200
Received: from [x.x.x.x] (port=6312 helo=test.local)
by myserver.com with esmtp (Exim 4.85)
(envelope-from <account@mydomain.com>)
id 1ZHEK8-00089t-W8
for account@mydomain.com; Mon, 20 Jul 2015 18:53:55 +0200
     
    #7 brandon45, Jul 21, 2015
  8. Martinho Novais

    Martinho Novais Registered

    Joined:
    Aug 19, 2015
    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    1
    Location:
    Portugal
    cPanel Access Level:
    Root Administrator
    Hi!

    I have the same problem. I already have active either SPF and DKIM to this account. But, if in the "Sender" is a valid email account, and the "Recipient" is a valid email account for the same domain or from the another domain in the same machine, the message is delivery without autentication.

    How you can see, who is generate this message is an IP address that isn't mine. (ceil.webhostingireland.ie - 91.210.235.40 )

    How can it is possible? Is there any kind of solution for this problem?

    Code:
    Delivery Event Details
[B]Event[/B]: success 
[B]Sender User[/B]: -remote-
[B]Sender Domain[/B]:
[B]Sender[/B]: [EMAIL]scxxxxira@sisxxxa4.pt[/EMAIL]
[B]Sent Time[/B]: Aug 19, 2015 4:19:04 AM
[B]Sender Host[/B]: ceil.domain.ie
[B]Sender IP[/B]: 91.210.235.40
[B]Authentication[/B]: localdelivery
[B]Spam Score[/B]: -1.2
[B]Recipient[/B]: [EMAIL]emxxxs@sisxxxa4.pt[/EMAIL]
[B]Delivered To[/B]: [EMAIL]emxxxs@sisxxxa4.pt[/EMAIL]
[B]deliveryuser[/B]: sisxxxa4
[B]deliverydomain[/B]: sisxxxa4.pt
[B]Router[/B]: virtual_user
[B]Transport[/B]: virtual_userdelivery
[B]Out Time[/B]: Aug 19, 2015 4:19:04 AM
[B]ID[/B]: 1ZRtuN-0006nX-QX
[B]Delivery Host[/B]: localhost
[B]Delivery IP[/B]: 127.0.0.1
[B]Size[/B]: 6.89 KB
[B]Result[/B]: Accepted
     
    #8 Martinho Novais, Aug 19, 2015
    Last edited by a moderator: Aug 19, 2015
  9. cPanelMichael

    cPanelMichael Forums Analyst
    Staff Member

    Joined:
    Apr 11, 2011
    Messages:
    34,852
    Likes Received:
    1,062
    Trophy Points:
    113
    cPanel Access Level:
    Root Administrator
    Hello :)

    Try enabling the "Reject SPF Failures" option if you want SPF records verified for incoming email. It's found under the "ACL Options" tab in "WHM Home » Service Configuration » Exim Configuration Manager".

    Thank you.
     
    #9 cPanelMichael, Aug 28, 2015
(You must log in or sign up to post here.)
Loading...
Similar Threads - Block local relay
  1. SuperBaby

    Hosting account not blocked after exceeding file size quota

    SuperBaby, May 20, 2017 at 8:10 PM, in forum: General Discussion
    Replies:
    5
    Views:
    47
    cPanelMichael
    May 22, 2017 at 12:55 PM
  2. GoWilkes

    Blocking RIPE, APNIC, AFRINIC, and LACNIC

    GoWilkes, May 9, 2017, in forum: Security
    Replies:
    1
    Views:
    43
    cPanelMichael
    May 10, 2017
  3. AndyB78

    unsuspend_login blocking hook

    AndyB78, May 8, 2017, in forum: cPanel Developers
    Replies:
    3
    Views:
    66
    cPanelMichael
    May 10, 2017
  4. RafaelEbarola

    Block incoming emails with malicious links

    RafaelEbarola, May 2, 2017, in forum: E-mail Discussions
    Replies:
    6
    Views:
    116
    RafaelEbarola
    May 4, 2017
  5. MichaelCropper

    cPHulk - Email Individual cPanel Account When Attacks are Blocked?

    MichaelCropper, May 1, 2017, in forum: E-mail Discussions
    Replies:
    1
    Views:
    57
    cPanelMichael
    May 2, 2017

Share This Page