From: Michael Tremer <michael.tremer@ipfire.org>
Date: Wed, 10 Dec 2025 17:10:01 +0000 (+0000)
Subject: util: Be more lax with domain names
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d5d7f832c4fb82478f3c512cca5f8ca94d5cb2ad;p=dnsbl.git

util: Be more lax with domain names

There are a lot of domain names out there that start/end with a
non-alphanumerical character which is why we need to remove this check.

We also need to accept underscores in domain names.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/dnsbl/util.py b/src/dnsbl/util.py
index 0e828d1..02924dd 100644
--- a/src/dnsbl/util.py
+++ b/src/dnsbl/util.py
@@ -101,10 +101,8 @@ def is_fqdn(s):
 	for label in labels:
 		if not 1 <= len(label) <= 63:
 			return False
-		if not label[0].isalnum() or not label[-1].isalnum():
-			return False
 		for ch in label:
-			if not (ch.isalnum() or ch == "-"):
+			if not ch.isalnum() or ch in "-_":
 				return False
 
 	return True