Cockroach Central is undergoing renovation. Your visit has been noted and will be subject to investigation.
You may be looking for these resources:
The Procmail Email Sanitizer home page
The Linux VPN Masquerade home page
tarpit.impsec.org - The impsec.org domain SMTP tarpit policy - if your MTA is wedged with dozens of processes trying to send spam to impsec.org email addresses, then take all impsec.org email addresses off of your spam mailing lists. It's that simple.