diff --git a/shadowsocks/asyncdns.py b/shadowsocks/asyncdns.py
index 01f2522..9713ec1 100644
--- a/shadowsocks/asyncdns.py
+++ b/shadowsocks/asyncdns.py
@@ -331,8 +331,8 @@ class DNSResolver(object):
             with open(etc_path, 'rb') as f:
                 for line in f.readlines():
                     line = line.strip()
-                    if "#" in line:
-                        line = line[:line.find('#')]
+                    if b"#" in line:
+                        line = line[:line.find(b'#')]
                     parts = line.split()
                     if len(parts) >= 2:
                         ip = parts[0]