You can try increasing process_limit for dns-client. Also installing nscd often helps (or a local resolver). Aki On 15/07/2024 16:51 EEST m--- via dovecot dovecot@dovecot.org wrote: When using DNS names for backends in a proxied setup, the async dns_client process after a short time of high load (burst scenario) seems to get overwhelmed: auth: Debug: conn unix:dns-client: dns(backend.local): Lookup failed after 0 msecs: Failed to connect to dns-client: Resource temporarily unavailable auth: Error: DNS lookup for backend.local failed: Failed to connect to dns-client: Resource temporarily unavailable The whole thing itself runs for a few thousand requests until this happens. ulimit nofile is set to 65000. When changing the backend from DNS name to IP, there is no problem. What are the possibilities to use dns names but without these problems? Any way to either increase dns resolving capacity OR cache the results for some time (or forever?)? Best regards _______________________________________________ dovecot mailing list -- dovecot@dovecot.org To unsubscribe send an email to dovecot-leave@dovecot.org