Use Gmail to filter spam from ISP email
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Works a charm! I have Gmail getting my email from my ISP, Eircon (misspelling intentional!), filtering the spam, and then Thunderbird is collecting what is left after all the multitudes of spam has been removed. I am not sending my outgoing email through Gmail SMTP server though as the “From” field on emails sent through Gmail contains “????????@gmail.com on behalf of ????????@eircom.net”, so still sending outgoing email through the Smart Telecom SMTP server. Not one spam message has got through yet!