There are several strategies to reduce the number of DNS lookups in your email marketing campaigns:
Optimize Images: Host images on a single, reliable server instead of multiple domains to reduce lookups. Limit Tracking: Use consolidated tracking URLs and reduce the number of third-party tracking codes. Use a CDN: A Content Delivery Network (CDN) can cache content and reduce DNS lookups. Check SPF/DKIM Records: Ensure your SPF and DKIM records are optimized and do not include too many DNS lookups.