Actually, the issue may not be on the mail server but like you said a machine on the network (which unfortunately is allowed to relay). First step would be to go via you logs and quarantine the culprit and run the scanning on the host. Some of the checks on the link sent to you earlier like Allow authenticated SMTP session may help but would require you to change settings on the clients which is viable in the shortrun if you manage a small LAN.

On Mon, Nov 23, 2009 at 4:30 PM, Simon Mbuthia <simon.mbuthia@gmail.com> wrote:
Shukran guys,

Will keep you posted on the progress... and by the way, does it mean that I should scan my mail server for malware? Coz my ISP says that a machine on my LAN is spamming. Should I run a virus scan as well [using a different tool coz KAV says it's as clean as a whistle]?

2009/11/23 Okechukwu <okechukwu@gmail.com>

I would first turn off the server before starting to explore - hoping
you have already done that.

./Ok3ch

On Mon, Nov 23, 2009 at 4:19 PM, Alex Nderitu <nderitualex@gmail.com> wrote:
> Check out this link
> http://www.altn.com/Support/KnowledgeBase/KnowledgeBaseResults/?Number=KBA-01366.
> Am not an mdaemon expert though, but mail server best practise should be to
> block open relay by only allowing trusted IPs to relay via your server.
>
> On Mon, Nov 23, 2009 at 4:15 PM, Rad! <conradakunga@gmail.com> wrote:
>>
>> Your server is probably a blind relay. See this
>> http://www.altn.com/Support/KnowledgeBase/KnowledgeBaseResults/?Number=KBA-01366
>>
>> On Mon, Nov 23, 2009 at 4:13 PM, Simon Mbuthia <simon.mbuthia@gmail.com>
>> wrote:
>>>
>>> Hi guys,
>>>
>>> I have just been informed by my ISP that our network is spamming :-( Some
>>> network engineer tells me that normally, it is the mail server that sends
>>> out SPAM. Our server happens t run MDaemon, whose configuration appears
>>> kinda cryptic to me. the said engineer tells me that there are settings that
>>> need to be applied on MDaemon to prevent it from spamming, but she doesn't
>>> remember exactly how that's done. It is on this basis that I am imploring
>>> MDaermon gurus [if there's such a thing as that] on the list to kindly throw
>>> me a lifeline as guys have started complaining of emails not getting
>>> delivered to their intended recipients.
>>>
>>>
>>> Please help.
>>>
>>>
>>> Me.
>>>
>>> --
>>> שִׁמְעוֹן
>>>
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