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SMTP Relay Questions

Discussion in 'Plesk for Linux - 8.x and Older' started by pstechnology, Dec 13, 2005.

  1. pstechnology

    pstechnology Guest

    My Plesk 7.5.4 server is set up for SMTP Auth required.

    I have several questions about this, and how to configure it.

    1. What advatages / side effects are there to setting a POP3 Lock time?

    2. I have a new client who want to host their mail with me, but they have been the victim several times of viruses that mass mail. Would it be advantageous to making them use their ISP's SMTP service, and my servers POP3 facility instead? What stops them guessing that the incoming and outgoing mail server names are the same though?

    3. Is there a way to monitor qmail queues and usage?

    There may be more questions later! :)
  2. wmchurch

    wmchurch Guest

    This is just how long the SMTP server will allow a message to relay off of it from the IP that the users authenticated via POP3 with. I usually set it somewhere between 15 and 20 minutes, typically our customers are fairly static so it's really not that much of a security issue. In all honesty, any worm that is using an SMTP server to send mail through could probably use the cached credentials to establish a pop3 session with that server as well to circumvent any of that. So I really don't see if being a tool that can help with that much, just prevents unauthorized users from relaying off of your server yet allowing authorized users to do just that. I prefer SMTP auth myself, but sometimes it's difficult to get users to configure it properly, and again if they are using cached credentials or actually using the mailer itself to propogate the worm it's not going to help. This is where a virus scanner on the SMTP server will come into play (at least stopping the spread of the worm).
    What's the intended benefit for this, and to who? Are you concerned that they may flood your server with spam or trojans? I would suggest probably using the anti-virus option from Plesk or from 4PSA. Depending on your size, it might be beneficial to have a dedicated mail gateway, we're implementing this now, plesk will forward all mail from qmail via SmartHost to our mail gateway which is a pretty high-end appliance that does mail filtering for Spam, Viruses, etc... All mail destined to the users in Plesk also go through this mail gateway.

    I know ART was working on a Postfix solution to this, where postfix handles the relaying for Qmail, but I don't know the status of this.

    From what I know, it all has to be done in a shell:

    Queue Statistics:

    List messages in the queue, shows sender, recipient, date and message number:

    qmHandle - a tool for the qmail queue:
    Pretty good all-in-one tool that will do most of the above plus more, I've not used it much in a Plesk environment, but I see no reason why it shouldn't work.

    Hope this helps.

  3. pstechnology

    pstechnology Guest

    Thanks for that. I already run Dr-Web on the server, so hopefully it will provide the protection req'd.
  4. wmchurch

    wmchurch Guest

    When it comes right down to it, it's the users responsibility to ensure their system is clean... Our AUP/TOS states this, but we usually try to assist them cleaning up their act by directing to http://www.avast.com and http://www.safer-networking.de/

  5. ShadowMan@

    ShadowMan@ Guest

    You should search these forums to see how many admins have had problems with Dr Web and ended up switching to alternatives such as the free version of clamav. Not to mention the use of qmail-scanner to coordinate the AV(s) and SpamAssassin scanning all emails in/out. Much better logging as well.