diff --git a/config/config.go b/config/config.go
index ee07e16..fb80e8c 100644
--- a/config/config.go
+++ b/config/config.go
@@ -126,7 +126,7 @@ type Listener struct {
 		Port            int      `sconf:"optional" sconf-doc:"Default 25."`
 		NoSTARTTLS      bool     `sconf:"optional" sconf-doc:"Do not offer STARTTLS to secure the connection. Not recommended."`
 		RequireSTARTTLS bool     `sconf:"optional" sconf-doc:"Do not accept incoming messages if STARTTLS is not active. Can be used in combination with a strict MTA-STS policy. A remote SMTP server may not support TLS and may not be able to deliver messages."`
-		DNSBLs          []string `sconf:"optional" sconf-doc:"Addresses of DNS block lists for incoming messages. Block lists are only consulted for connections/messages without enough reputation to make an accept/reject decision. This prevents sending IPs of all communications to the block list provider. If any of the listed DNSBLs contains a requested IP address, the message is rejected as spam. The DNSBLs are checked for healthiness before use, at most once per 4 hours. Example DNSBLs: sbl.spamhaus.org, bl.spamcop.net"`
+		DNSBLs          []string `sconf:"optional" sconf-doc:"Addresses of DNS block lists for incoming messages. Block lists are only consulted for connections/messages without enough reputation to make an accept/reject decision. This prevents sending IPs of all communications to the block list provider. If any of the listed DNSBLs contains a requested IP address, the message is rejected as spam. The DNSBLs are checked for healthiness before use, at most once per 4 hours. Example DNSBLs: sbl.spamhaus.org, bl.spamcop.net. See https://www.spamhaus.org/sbl/ and https://www.spamcop.net/ for more information and terms of use."`
 
 		FirstTimeSenderDelay *time.Duration `sconf:"optional" sconf-doc:"Delay before accepting a message from a first-time sender for the destination account. Default: 15s."`
 
diff --git a/config/doc.go b/config/doc.go
index 59b577a..1328429 100644
--- a/config/doc.go
+++ b/config/doc.go
@@ -172,7 +172,8 @@ describe-static" and "mox config describe-domains":
 				# block list provider. If any of the listed DNSBLs contains a requested IP
 				# address, the message is rejected as spam. The DNSBLs are checked for healthiness
 				# before use, at most once per 4 hours. Example DNSBLs: sbl.spamhaus.org,
-				# bl.spamcop.net (optional)
+				# bl.spamcop.net. See https://www.spamhaus.org/sbl/ and https://www.spamcop.net/
+				# for more information and terms of use. (optional)
 				DNSBLs:
 					-