diff --git a/nsupdate/main/migrations/0008_auto_20151228_1342.py b/nsupdate/main/migrations/0008_auto_20151228_1342.py
new file mode 100644
index 0000000..e665311
--- /dev/null
+++ b/nsupdate/main/migrations/0008_auto_20151228_1342.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0007_auto_20150425_1741'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='relatedhost',
+            name='interface_id_ipv6',
+            field=models.CharField(default=b'', max_length=40, blank=True, help_text='The IPv6 interface ID of this host. Use IPv6 notation. Empty = do not set record.', null=True, verbose_name='interface ID IPv6'),
+            preserve_default=True,
+        ),
+    ]
diff --git a/nsupdate/main/models.py b/nsupdate/main/models.py
index 8aa0126..dc325dc 100644
--- a/nsupdate/main/models.py
+++ b/nsupdate/main/models.py
@@ -385,12 +385,12 @@ class RelatedHost(models.Model):
     interface_id_ipv4 = models.CharField(
         _("interface ID IPv4"),
         default='', blank=True, null=True,
-        max_length=16,  # 123.123.123.123
+        max_length=16,
         help_text=_("The IPv4 interface ID of this host. Use IPv4 notation. Empty = do not set record."))
     interface_id_ipv6 = models.CharField(
         _("interface ID IPv6"),
         default='', blank=True, null=True,
-        max_length=22,  # ::1234:5678:9abc:def0
+        max_length=40,
         help_text=_("The IPv6 interface ID of this host. Use IPv6 notation. Empty = do not set record."))
     available = models.BooleanField(
         _("available"),