# Sendmail performance



## balanga (Jun 23, 2016)

In some notes for integrating Mailman with Sendmail it says:-


> 6.3.3 Performance notes
> 
> One of the surest performance killers for Sendmail users is when
> Sendmail is configured to synchronously verify the recipient's host via
> ...



So how do I configure Sendmail to not do DNS verification synchronously for  localhost connections?


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## leebrown66 (Jun 24, 2016)

It's 10 years old, but maybe this will help.


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