diff --git a/dendrite-config.yaml b/dendrite-config.yaml
index 0ea584aa..31b83066 100644
--- a/dendrite-config.yaml
+++ b/dendrite-config.yaml
@@ -112,7 +112,7 @@ global:
     # Maximum number of entries to hold in the DNS cache, and
     # for how long those items should be considered valid in seconds.
     cache_size: 256
-    cache_lifetime: 300
+    cache_lifetime: "5m" # 5minutes; see https://pkg.go.dev/time@master#ParseDuration for more
 
 # Configuration for the Appservice API.
 app_service_api:
diff --git a/setup/base.go b/setup/base.go
index 7b691608..1a52d1c2 100644
--- a/setup/base.go
+++ b/setup/base.go
@@ -139,15 +139,14 @@ func NewBaseDendrite(cfg *config.Dendrite, componentName string, useHTTPAPIs boo
 
 	var dnsCache *gomatrixserverlib.DNSCache
 	if cfg.Global.DNSCache.Enabled {
-		lifetime := time.Second * cfg.Global.DNSCache.CacheLifetime
 		dnsCache = gomatrixserverlib.NewDNSCache(
 			cfg.Global.DNSCache.CacheSize,
-			lifetime,
+			cfg.Global.DNSCache.CacheLifetime,
 		)
 		logrus.Infof(
 			"DNS cache enabled (size %d, lifetime %s)",
 			cfg.Global.DNSCache.CacheSize,
-			lifetime,
+			cfg.Global.DNSCache.CacheLifetime,
 		)
 	}