diff --git a/src/common/core/blacklist/jobs/blacklist-download.py b/src/common/core/blacklist/jobs/blacklist-download.py
index 734534069..6c966b871 100755
--- a/src/common/core/blacklist/jobs/blacklist-download.py
+++ b/src/common/core/blacklist/jobs/blacklist-download.py
@@ -23,7 +23,7 @@ from Database import Database
 from logger import setup_logger
 from jobs import cache_file, cache_hash, is_cached_file, file_hash
 
-rdns_rx = re_compile(rb"^(\.?[a-z\d\-]+)*\.[a-z]{2,}$", IGNORECASE)
+rdns_rx = re_compile(rb"^[^ ]+$", IGNORECASE)
 asn_rx = re_compile(rb"^\d+$")
 uri_rx = re_compile(rb"^/")
 
diff --git a/src/common/core/greylist/jobs/greylist-download.py b/src/common/core/greylist/jobs/greylist-download.py
index c5ce106b9..4dcdab421 100755
--- a/src/common/core/greylist/jobs/greylist-download.py
+++ b/src/common/core/greylist/jobs/greylist-download.py
@@ -23,7 +23,7 @@ from Database import Database
 from logger import setup_logger
 from jobs import cache_file, cache_hash, is_cached_file, file_hash
 
-rdns_rx = re_compile(rb"^(\.?[a-z\d\-]+)*\.[a-z]{2,}$", IGNORECASE)
+rdns_rx = re_compile(rb"^[^ ]+$", IGNORECASE)
 asn_rx = re_compile(rb"^\d+$")
 uri_rx = re_compile(rb"^/")
 
diff --git a/src/common/core/whitelist/jobs/whitelist-download.py b/src/common/core/whitelist/jobs/whitelist-download.py
index 9621a54eb..8fce9bff0 100755
--- a/src/common/core/whitelist/jobs/whitelist-download.py
+++ b/src/common/core/whitelist/jobs/whitelist-download.py
@@ -23,7 +23,7 @@ from Database import Database
 from logger import setup_logger
 from jobs import cache_file, cache_hash, is_cached_file, file_hash
 
-rdns_rx = re_compile(rb"^(\.?[a-z\d\-]+)*\.[a-z]{2,}$", IGNORECASE)
+rdns_rx = re_compile(rb"^[^ ]+$", IGNORECASE)
 asn_rx = re_compile(rb"^\d+$")
 uri_rx = re_compile(rb"^/")