malloc4k's questions

I run a Postfix mail server using Spamassassin as after-queue filter.

It works quite well, but sometimes I get spam from the network that has correct MAIL FROM: address, but also contains, in DATA: section, different forged address something <at> mydomain.com.

Most e-mail client programs, including Thunderbird and Outlook, displays it using the second ( forged ) address.

I would like to block such messages automatically, but I can't do it using smtpd_recipient_restrictions ( forged address resides in DATA: section ).

It also have nothing to do with SPF since MAIL FROM: ( envelope sender ) address may be correct according to SPF.

Then how can I do it using Postfix settings or Spamassassin rules ?

I have an e-mail server powered by Postfix. Aside from traditional e-mail accounts on my server, I want to maintain some accounts whose only role is to forward all incoming mail to differnet address on different mail system.

For example. I own domain example.com and I set account with address [email protected] on my server. And I want this one account to forward all incoming messages to mailbox in different mail system, in domain that does not belong to me [email protected]. I know, that i can add an entry in in my virtual_alias_maps lookup table.

[email protected]   [email protected]

But I'm worried that to deliver message, Postfix will use original envelope sender address. It's okay if sender is from domain example.com that belongs to me, but otherwise stranger.net server may classify this message as a spam.

Is there some way, to alter envelope sender on delivery ?

Are smtp_generic_maps ment for this ?

If so, is it okay, that my server sends an e-mail using specific envelope sender, and then something else in message being forwarded ?

How else to deal with such problem ?

I have a LAN behind a Linksys RV016 Router. It is connected to the internet with DSL line with asymetric parameters 2Mbit download / 512 kbit upload.

In this LAN I have MS SQL server, and i want to connect to it remotely via VPN. To do this I use my RV016 router's PPTP function. Connection works fine, but ... little to slow.

And here is my question: what may be the bottleneck - is it only my DSL line's speed parameters ? Or may it be caused ALSO by router's hardware parameters (processor, RAM) ? In that case is it reasonalbe to set additional server VPN server inside the LAN, so that router only forwars communication on appropriate port and the rest is up to VPN server ?

A question from a beginner Postfix admin. What is the exact difference between writing in main.cf:

smtpd_reject_unlisted_sender = yes

and

smtpd_sender_restrictions =
    reject_unlisted_sender

?

Is there a real difference in operation or is smtpd_reject_unlisted_sender just a way to enforce this restriction when some of rules listed in smtpd_sender_restrictions results in PERMIT ?

By default when I access some computer's share ( typing \\hostname in Windows Explorer ) Windows passes credential of my current user. It prompts for credentials only when current user's credentials are incorrect.

Is there some way to force Windows not to pass current user's credentails, but prompt for them ? I thought about making use of net view command, but it doesn't grab 'user' and 'password' parameters.

How to decide if wiring in office / server room qualifies for replacement ?

I have Windows Server 2003 with CopSSH installed on it ( Cygwin + sshd ). I would like to be able to run a PowerShell script via SSH session command and then use its output. Is there such a capability? How to do it?

Suppose we have Windows Server 2008 R2 without any RDS CAL's. Is it possible to give access to Remote Desktop to a user which is not in 'Administrators' group ? I've tried everything and it seems that it is not, but I may be wrong.