Email getting and sending

[Jorge Fábregas]

On Saturday 24 July 2004 2:21 pm, John Thompson wrote:
> Many ISPs have taken to blocking port 25 connections from dynamic IP
> addesses as these are frequently spam bots.  Instead, tell sendmail to
> use your ISP's smtp service as a "smart host" --
> define(`SMART_HOST',`smtp.your.provider') in sendmail.mc, generate a new
> sendmail.cf by running "make -C /etc/mail" and restart sendmail.  Your
> outbound email will be routed through your ISP's smtp service for delivery.

Why would you do that? Instead of specifying your ISP's MTA in your MUA? Any 
benefit?