Aleš Krajník's questions

I have a Linux server with local accounts (they are used by PHP-FPM processes) that are using Postfix's sendmail binary to send e-mails.

All e-mails are sent through local Postfix to a central mailhub that considers e-mails from hosting server as trustworthy, to some degree (they are trusted more then e-mails from the internet).

The problem is that any local user can send e-mail as any sender (parameter -f of the sendmail binary, or Return-Path).

I would like to limit allowed senders per a user - that is to define which user can send e-mails as which sender / sender domain. When a user then would send an e-mail as wrong sender, the e-mail should be dropped.

I did not find any solution to map UID or local username to sender.

The only solution I found is use a SMTP instead, to create a Postfix account and password for each local user and then use directive like reject_sender_login_mismatch in smtpd_sender_restrictions. That is more difficult to configure and maintain and is not using the benefit of the fact the users are already authenticated by system and I would like to avoid that.

I am not able to find this information or to Google it so here it is:

Me and a friend share 1 account on Windows Server 2012 (R2 Datacenter) virtual server. We use this to host one application and there is no need to use it few times per day at maximum so one shared account is fine with us. We connect using RDP.

It happens that when he is logged in and I try to log-in, it forces him to log off. Now, I remember, that in past I used a RDP connection on older version of Windows Server (configured by someone else) and it always asked, whether I wanted to continue with logging and disconnect currently logged user or stop the action.

Is that possible on my server - that is ask before disconnecting currently logged user?

Thanks :-)

I discovered a change in some recent version of ProFTPd - I used Umask 0007 to remove permissions to "others" but it kept my SetGID directory flag - which is what I wanted.

In recent version (1.3.4) my permission system stopped to work. I am unable to convince ProFTPd to set SetGID flag on newly created directories.

In documentation they say "base-mode" for creating directories is 0777 and UMask allows only to remove permissions.

How to make it set SetGID bit on new directories, that is permissions 2770?

Thanks.