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Do you obfuscate email headers when reporting spam issues to clients?
- Subject: Do you obfuscate email headers when reporting spam issues to clients?
- From: dclements at gmail.com (Doug Clements)
- Date: Wed, 6 Nov 2013 17:09:19 -0500
- In-reply-to: <CAP-guGWwf=hVUWatmn14v-7Ssor29WQ8tJpoyJJZ+S5Gcf3j+w@mail.gmail.com>
- References: <CABgOHgvOjdyk8Wg6zh7D6m2JrBa1ErQhqMHQX3=2XuY9HE_zGg@mail.gmail.com> <CAP-guGWwf=hVUWatmn14v-7Ssor29WQ8tJpoyJJZ+S5Gcf3j+w@mail.gmail.com>
On Wed, Nov 6, 2013 at 4:45 PM, William Herrin <bill at herrin.us> wrote:
> Incidentally, I'd suggest that an ounce of prevention is worth a pound
> of cure. Simply block outbound tcp port 25 for new hosting customers
> on a "tell me if you want it open" basis.
>
>
Or to thwart those clever spammers, block inbound SYN/ACK packets with a
source port of 25. This catches the ones who send SYNs out other providers
with your network's source addresses which bypasses most simple ACLs.
--Doug