Re: home server for email box

[Yassine Chaouche <a.chaouche@algerian-radio.dz>]

Le 3/10/23 à 12:44, tomas@tuxteam.de a écrit :
> On Fri, Mar 10, 2023 at 12:01:57PM +0100, Nicolas George wrote:
> > pyh@ymail.ne.jp (12023-03-10):
> > > Can I setup a mail server (postfix, dovecot, dkim, rspamd etc) on this box to receive/send email normally?
> >
> > Probably not: ISP declare IP blocks attributed to clients as “domestic”
> > and a lot of important e-mail operators block them.
>
> It makes sense to check for that. But having a static routable IP
> is a strong hint that it could work.
>
> Have you more details for that "declaration" you hint at? How is
> an IP "declared" as "domestic"?

If your IP is listed in the PBL,
then your ISP has declared it as domestic
(not supposed to send mail)

I use a simple bash function to know if an IP is listed or not in spamhaus ZEN list.

function net.ip.reverse(){ local IFS; IFS=.; set -- $1; echo $4.$3.$2.$1; }

function net.ip.reputation(){
    revip=$(net.ip.reverse "$1")
    results=$(dig +short $revip.zen.spamhaus.org)
    [[ -z $results ]] && (echo "clean"; return 0)
    for result in $results
    do
        case "$result" in
            127.0.0.2)
                echo "SBL : SPAM sender"
                ;;
            127.0.0.3)
                echo "CSS : snowshoe"
                ;;
            127.0.0.[4-7])
                echo "XBL/CBL: trojans, exploits"
                ;;
            127.0.0.1[01])
                echo "PBL(ISP) : not supposed to send mail"
                ;;
        esac
    done
    return 1
}

Beware that this function doesn't work if you use an open resolver like 8.8.8.8/8.8.4.4.
If you don't have your own DNS server setup,
you can try with OpenDNS servers
(208.67.222.222/208.67.220.220)

You can use the OpenDNS resolver by changing this line:
    results=$(dig +short $revip.zen.spamhaus.org 208.67.222.222)

Some examples:

root@messagerie-principale[10.10.10.19] ~ # mail.spam.report | grep -o $REGX_IP | sort | uniq | head -3 | while read IP; do echo $IP; net.ip.reputation $IP; done;
101.43.66.163
XBL/CBL: trojans, exploits
102.152.254.85
XBL/CBL: trojans, exploits
PBL(ISP) : not supposed to send mail
103.132.168.165
XBL/CBL: trojans, exploits
PBL(ISP) : not supposed to send mail
root@messagerie-principale[10.10.10.19] ~ #

Best,

--
yassine -- sysadm
+213-779 06 06 23
http://about.me/ychaouche
Looking for side gigs.