Hi,

I have a dedicated server running linux, i have running nwebmail for users to send email via sendmail

the problem i have is that the users are able to send mail outwards with domains other than the ones we own.

this is a big security problem and one i need to clamp down on this immediately

how do i stop this

many thanks

R Martin

Originally posted by rmartin
the problem i have is that the users are able to send mail outwards with domains other than the ones we own.
how do i stop this


Have you checked your list of domains for which to relay, and verified that no top-level domains are in there? (for example if it's set to relay for .com - it will happily do so)

It would be a good idea to install POP-B4-SMTP or perhaps a new version of Sendmail with SMTP-AUTH.

in webmin under relay domains i have listed the main domain name + the ip of the machine eg

domain.co.uk
80.70.3.1

that is all

but users can set their from address to whatever they like and the machine will send the mail

many thanks

r martin

Originally posted by rmartin
but users can set their from address to whatever they like and the machine will send the mail


Now I understand you.

Do you want to block users completely from sending mail?

Or do you just want the sender address to be one of the domains hosted on the box?

Originally posted by jks


Or do you just want the sender address to be one of the domains hosted on the box?

I would really want this to happen

Many thanks

R Martin

Hi,

I have had to disable parts of the webmail system to prevent this happening but this does not solve the overall problem

Anyone could put webmail of scripts on our system to carry on doing this,

I need to get the system to reject fake FROM address originating from our system

You help is appreciated

Many Thanks

R Martin