From 0538c3040f65dea97a8e98eab7be2c8fc8ff17a9 Mon Sep 17 00:00:00 2001
From: Nathaniel McCallum <npmccallum@redhat.com>
Date: Fri, 5 Dec 2014 11:18:55 -0500
Subject: [PATCH] Prefer TCP connections to UDP in krb5 clients

In general, TCP is a better fit for FreeIPA due to large packet sizes.

However, there is also a specific need for TCP when using OTP. If a UDP
packet is delivered to the server and the server takes longer to process
it than the client timeout (likely), the OTP value will be resent.
Unfortunately, this will cause failures or even lockouts. Switching to
TCP avoids this problem altogether.

https://fedorahosted.org/freeipa/ticket/4725

Reviewed-By: Martin Kosek <mkosek@redhat.com>
---
 install/share/krb5.conf.template          | 1 +
 install/tools/ipa-replica-conncheck       | 1 +
 ipa-client/ipa-install/ipa-client-install | 1 +
 3 files changed, 3 insertions(+)

diff --git a/install/share/krb5.conf.template b/install/share/krb5.conf.template
index 7c82083e3331cfacccc1995cd9dfa6ddd88edd1f..6cb5ee34704cd6158e882bfa89fc597f3ff1bb0f 100644
--- a/install/share/krb5.conf.template
+++ b/install/share/krb5.conf.template
@@ -12,6 +12,7 @@ includedir /var/lib/sss/pubconf/krb5.include.d/
  rdns = false
  ticket_lifetime = 24h
  forwardable = yes
+ udp_preference_limit = 0
 $OTHER_LIBDEFAULTS
 [realms]
  $REALM = {
diff --git a/install/tools/ipa-replica-conncheck b/install/tools/ipa-replica-conncheck
index 88e42bafbc600fb7c36b7727c770e75edccd2196..22348fc2158e59afc2e1aa51e3d3f51e90b99e39 100755
--- a/install/tools/ipa-replica-conncheck
+++ b/install/tools/ipa-replica-conncheck
@@ -208,6 +208,7 @@ def configure_krb5_conf(realm, kdc, filename):
     libdefaults.append({'name':'rdns', 'type':'option', 'value':'false'})
     libdefaults.append({'name':'ticket_lifetime', 'type':'option', 'value':'24h'})
     libdefaults.append({'name':'forwardable', 'type':'option', 'value':'yes'})
+    libdefaults.append({'name':'udp_preference_limit', 'type':'option', 'value':'0'})
 
     opts.append({'name':'libdefaults', 'type':'section', 'value': libdefaults})
     opts.append({'name':'empty', 'type':'empty'})
diff --git a/ipa-client/ipa-install/ipa-client-install b/ipa-client/ipa-install/ipa-client-install
index 7b1e2f8b0b873375c14d02558dce65b68a5ad173..75a1711a7e1fdc9359ad02d55ad94d65af51ea93 100755
--- a/ipa-client/ipa-install/ipa-client-install
+++ b/ipa-client/ipa-install/ipa-client-install
@@ -1047,6 +1047,7 @@ def configure_krb5_conf(cli_realm, cli_domain, cli_server, cli_kdc, dnsok,
     libopts.append({'name':'rdns', 'type':'option', 'value':'false'})
     libopts.append({'name':'ticket_lifetime', 'type':'option', 'value':'24h'})
     libopts.append({'name':'forwardable', 'type':'option', 'value':'yes'})
+    libopts.append({'name':'udp_preference_limit', 'type':'option', 'value':'0'})
 
     # Configure KEYRING CCACHE if supported
     if kernel_keyring.is_persistent_keyring_supported():
-- 
2.1.0