Re: postfix security configuration
Tarjei Huse wrote: This might help: http://jimsun.linxnet.com/misc/postfix-anti-UCE.txt On Mon, 2003-08-11 at 13:37, Marcel Weber wrote: Another good thing is the postfix ([EMAIL PROTECTED]) mailing list. It is quite a high traffic mailing list, but there are very expirienced people reading it... (I mean if Wietse doesn't know how this is most nicely done, who else?) Regards Marcel pgp0.pgp Description: PGP signature
Re: postfix security configuration
This might help: http://jimsun.linxnet.com/misc/postfix-anti-UCE.txt On Mon, 2003-08-11 at 13:37, Marcel Weber wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Am Montag, 11.08.03, um 12:59 Uhr (Europe/Zurich) schrieb Tomasz Papszun: If you want to prevent them from using non existing sender addresses from your domain, you can do it by creating a file (lookup table) for postmap(1), containing all allowed addresses with OK and another table containing your domainname with REJECT. If you want to prevent them from using sender addresses from other domain, it's also possible with properly prepared config. If you want to prevent them from using other (not their own) sender addresses from your domain, you must use SMTP AUTH, I'm afraid. -- Tomasz Papszun SysAdm @ TP S.A. Lodz, Poland | And it's only [EMAIL PROTECTED] http://www.lodz.tpsa.pl/ | ones and zeros. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED] Theoretically there is another possibility. Actually pop-before-smtp does nothing than watching the log file, picking the ip address of the pop client and putting this address for a certain time into a postmap for postfix. If you would use the user's email address as his pop3 login name (within a sql or ldap db, for example), one could take this information and write it into another postmap file. This would necessite some modification of the pop-before-smtp script, but I think it wouldn't be too hard to implement. It wouldn't be perfect, though: Imagine two users logged in at the same time. Under this situation each user could abuse the other user's email address. For a really secure system, there is no way around smtp auth. pop-before-smtp relies on ip addresses. But what about NAT? Users coming from a private masqueraded network, could misuse your server at their pleasure, if one user from this network has logged into his pop3 account. Regards Marcel -BEGIN PGP SIGNATURE- iD8DBQE/N3/y1EXMUTKVE5URAjPsAKD1sVpkeqHSIcYnungYkuF/fNyumgCg7pmF o2GTZhfgn7NnZ63P8HLSpEI= =B+0b -END PGP SIGNATURE- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: postfix security configuration
On Sun, 10 Aug 2003 at 10:26:16 +, Fallen Angel wrote: my config: debian stable 3.0r1 postfix qpopper I have a small problem: my smtp after pop3 configuration works fine, no open relay possible, but the authentificated users can fake their own e-mail address. How can I stop it, so they can only use the adress which were set up for them. thx for help Konstantin If you want to prevent them from using non existing sender addresses from your domain, you can do it by creating a file (lookup table) for postmap(1), containing all allowed addresses with OK and another table containing your domainname with REJECT. If you want to prevent them from using sender addresses from other domain, it's also possible with properly prepared config. If you want to prevent them from using other (not their own) sender addresses from your domain, you must use SMTP AUTH, I'm afraid. -- Tomasz Papszun SysAdm @ TP S.A. Lodz, Poland | And it's only [EMAIL PROTECTED] http://www.lodz.tpsa.pl/ | ones and zeros. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: postfix security configuration
Am Son, 2003-08-10 um 12.26 schrieb Fallen Angel: hi, my config: debian stable 3.0r1 postfix qpopper I have a small problem: my smtp after pop3 configuration works fine, no open relay possible, but the authentificated users can fake their own e-mail address. How can I stop it, so they can only use the adress which were set up for them. As i know, only by adding reject_sender_login_mismatch to smtpd_sender_restrictions. Be careful about the order of your restrictions under smtpd_sender_restrictions. Look for the exact syntax in postfix docs on your machine. And : you'll need to smtp-auth your smtp-clients with sasl for postfix-smtpd. This information is from postfix 2.0.3. Im using this with cyrus 2.1 and sasl 2.2 from http://people.debian.org/~hmh. -- Wilfried Essig -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: postfix security configuration
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Am Montag, 11.08.03, um 12:59 Uhr (Europe/Zurich) schrieb Tomasz Papszun: If you want to prevent them from using non existing sender addresses from your domain, you can do it by creating a file (lookup table) for postmap(1), containing all allowed addresses with OK and another table containing your domainname with REJECT. If you want to prevent them from using sender addresses from other domain, it's also possible with properly prepared config. If you want to prevent them from using other (not their own) sender addresses from your domain, you must use SMTP AUTH, I'm afraid. -- Tomasz Papszun SysAdm @ TP S.A. Lodz, Poland | And it's only [EMAIL PROTECTED] http://www.lodz.tpsa.pl/ | ones and zeros. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED] Theoretically there is another possibility. Actually pop-before-smtp does nothing than watching the log file, picking the ip address of the pop client and putting this address for a certain time into a postmap for postfix. If you would use the user's email address as his pop3 login name (within a sql or ldap db, for example), one could take this information and write it into another postmap file. This would necessite some modification of the pop-before-smtp script, but I think it wouldn't be too hard to implement. It wouldn't be perfect, though: Imagine two users logged in at the same time. Under this situation each user could abuse the other user's email address. For a really secure system, there is no way around smtp auth. pop-before-smtp relies on ip addresses. But what about NAT? Users coming from a private masqueraded network, could misuse your server at their pleasure, if one user from this network has logged into his pop3 account. Regards Marcel -BEGIN PGP SIGNATURE- iD8DBQE/N3/y1EXMUTKVE5URAjPsAKD1sVpkeqHSIcYnungYkuF/fNyumgCg7pmF o2GTZhfgn7NnZ63P8HLSpEI= =B+0b -END PGP SIGNATURE- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
postfix security configuration
hi, my config: debian stable 3.0r1 postfix qpopper I have a small problem: my smtp after pop3 configuration works fine, no open relay possible, but the authentificated users can fake their own e-mail address. How can I stop it, so they can only use the adress which were set up for them. thx for help Konstantin ___ auf nummer sicher studieren: mit der semester-police der ace insurance sind studenten auch bei studienunterbrechungen und -abbruch durch krankheit oder unfall rundum gut abgesichert: http://www.firstcampus.com/de/semesterpolice -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: postfix security configuration
On Sun, 10 Aug 2003 at 10:26:16 +, Fallen Angel wrote: my config: debian stable 3.0r1 postfix qpopper I have a small problem: my smtp after pop3 configuration works fine, no open relay possible, but the authentificated users can fake their own e-mail address. How can I stop it, so they can only use the adress which were set up for them. thx for help Konstantin If you want to prevent them from using non existing sender addresses from your domain, you can do it by creating a file (lookup table) for postmap(1), containing all allowed addresses with OK and another table containing your domainname with REJECT. If you want to prevent them from using sender addresses from other domain, it's also possible with properly prepared config. If you want to prevent them from using other (not their own) sender addresses from your domain, you must use SMTP AUTH, I'm afraid. -- Tomasz Papszun SysAdm @ TP S.A. Lodz, Poland | And it's only [EMAIL PROTECTED] http://www.lodz.tpsa.pl/ | ones and zeros.
Re: postfix security configuration
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Am Montag, 11.08.03, um 12:59 Uhr (Europe/Zurich) schrieb Tomasz Papszun: If you want to prevent them from using non existing sender addresses from your domain, you can do it by creating a file (lookup table) for postmap(1), containing all allowed addresses with OK and another table containing your domainname with REJECT. If you want to prevent them from using sender addresses from other domain, it's also possible with properly prepared config. If you want to prevent them from using other (not their own) sender addresses from your domain, you must use SMTP AUTH, I'm afraid. -- Tomasz Papszun SysAdm @ TP S.A. Lodz, Poland | And it's only [EMAIL PROTECTED] http://www.lodz.tpsa.pl/ | ones and zeros. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED] Theoretically there is another possibility. Actually pop-before-smtp does nothing than watching the log file, picking the ip address of the pop client and putting this address for a certain time into a postmap for postfix. If you would use the user's email address as his pop3 login name (within a sql or ldap db, for example), one could take this information and write it into another postmap file. This would necessite some modification of the pop-before-smtp script, but I think it wouldn't be too hard to implement. It wouldn't be perfect, though: Imagine two users logged in at the same time. Under this situation each user could abuse the other user's email address. For a really secure system, there is no way around smtp auth. pop-before-smtp relies on ip addresses. But what about NAT? Users coming from a private masqueraded network, could misuse your server at their pleasure, if one user from this network has logged into his pop3 account. Regards Marcel -BEGIN PGP SIGNATURE- iD8DBQE/N3/y1EXMUTKVE5URAjPsAKD1sVpkeqHSIcYnungYkuF/fNyumgCg7pmF o2GTZhfgn7NnZ63P8HLSpEI= =B+0b -END PGP SIGNATURE-
Re: postfix security configuration
This might help: http://jimsun.linxnet.com/misc/postfix-anti-UCE.txt On Mon, 2003-08-11 at 13:37, Marcel Weber wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Am Montag, 11.08.03, um 12:59 Uhr (Europe/Zurich) schrieb Tomasz Papszun: If you want to prevent them from using non existing sender addresses from your domain, you can do it by creating a file (lookup table) for postmap(1), containing all allowed addresses with OK and another table containing your domainname with REJECT. If you want to prevent them from using sender addresses from other domain, it's also possible with properly prepared config. If you want to prevent them from using other (not their own) sender addresses from your domain, you must use SMTP AUTH, I'm afraid. -- Tomasz Papszun SysAdm @ TP S.A. Lodz, Poland | And it's only [EMAIL PROTECTED] http://www.lodz.tpsa.pl/ | ones and zeros. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED] Theoretically there is another possibility. Actually pop-before-smtp does nothing than watching the log file, picking the ip address of the pop client and putting this address for a certain time into a postmap for postfix. If you would use the user's email address as his pop3 login name (within a sql or ldap db, for example), one could take this information and write it into another postmap file. This would necessite some modification of the pop-before-smtp script, but I think it wouldn't be too hard to implement. It wouldn't be perfect, though: Imagine two users logged in at the same time. Under this situation each user could abuse the other user's email address. For a really secure system, there is no way around smtp auth. pop-before-smtp relies on ip addresses. But what about NAT? Users coming from a private masqueraded network, could misuse your server at their pleasure, if one user from this network has logged into his pop3 account. Regards Marcel -BEGIN PGP SIGNATURE- iD8DBQE/N3/y1EXMUTKVE5URAjPsAKD1sVpkeqHSIcYnungYkuF/fNyumgCg7pmF o2GTZhfgn7NnZ63P8HLSpEI= =B+0b -END PGP SIGNATURE-
postfix security configuration
hi, my config: debian stable 3.0r1 postfix qpopper I have a small problem: my smtp after pop3 configuration works fine, no open relay possible, but the authentificated users can fake their own e-mail address. How can I stop it, so they can only use the adress which were set up for them. thx for help Konstantin ___ auf nummer sicher studieren: mit der semester-police der ace insurance sind studenten auch bei studienunterbrechungen und -abbruch durch krankheit oder unfall rundum gut abgesichert: http://www.firstcampus.com/de/semesterpolice
