Bug 451936 - ipa-server-install fails due to rpcbind taking 750/udp
ipa-server-install fails due to rpcbind taking 750/udp
Product: freeIPA
Classification: Community
Component: ipa-server (Show other bugs)
All Linux
medium Severity high
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Assigned To: Simo Sorce
Chandrasekar Kannan
Depends On:
Blocks: 453489
  Show dependency treegraph
Reported: 2008-06-18 04:57 EDT by Alan Pevec
Modified: 2015-01-04 18:32 EST (History)
5 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2008-08-04 14:21:08 EDT
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description Alan Pevec 2008-06-18 04:57:17 EDT
Description of problem:
restarting the KDC
Unexpected error - see ipaserver-install.log for details:
Command '/sbin/service krb5kdc restart' returned non-zero exit status 1
krb5kdc: Address already in use - Cannot bind server socket to port 750 address
lsof +M -n shows|grep rpcbind shows:
rpcbind 1423 rpc 6u IPv4 3003 UDP *:sunrpc[portmapper] 
rpcbind 1423 rpc 7u IPv4 3007 UDP *:kerberos-iv 
rpcbind 1423 rpc 8u IPv4 3008 TCP *:sunrpc[portmapper] (LISTEN)

If udp transport (tpi_clts) is defined in /etc/netconfig, rpcbind will bind on
startup to a random UDP port in reserved range 600-1024, in addition to its
standard port 111 (Ccing rpcbind owner to comment)

As luck would have it, that port turns out to be 750 (krb4 port) frequently when
running ipa-server-install at first boot in appliance http://ovirt.org/

Workaround is to disable UDP transports in /etc/netconfig in kickstart %post:
sed -i -e 's/^\(udp\)/#\1/' /etc/netconfig 

Version-Release number of selected component (if applicable):

How reproducible:
sporadic, when rpcbind gets the right PID
libtirpc-0.1.7/src/bindresvport.c:122 port = (getpid() % NPORTS) + STARTPORT;

Steps to Reproduce:
1. while /bin/true; do service rpcbind restart >/dev/null; port=$(lsof +M -nPi
UDP|grep ^rpcbind|grep -v portmapper|cut -d: -f2); echo -n "$port"; if [[
"$port" == "750 " ]]; then echo KABOOM; exit; fi; done
2. ipa-server-install
Actual results:
ipa-server-install fails

Expected results:
Well, ideally rpcbind won't take random port in 600-1024...
but ipa-server-install should check all ports it needs are free in a
pre-installation  check

Additional info:
backtrace where the 2nd UDP port is bound:
#0  bindresvport_sa (sd=10, sa=0xbfc16fb8) at bindresvport.c:132
#1  0x0014eb24 in bindresvport (sd=10, sin=0x0) at bindresvport.c:59
#2  0x0015d60a in svc_tli_create (fd=10, nconf=0x0, bindaddr=0x0, sendsz=0,
recvsz=0) at svc_generic.c:224 
#3  0xb8014eb6 in create_rmtcall_fd (nconf=0xb832e940) at rpcb_svc_com.c:515
#4  0xb80117f7 in init_transport (nconf=0xb832e940) at rpcbind.c:645
#5  0xb8011c8d in main (argc=2, argv=0xbfc173a4) at rpcbind.c:182
Comment 1 Alan Pevec 2008-06-18 05:04:08 EDT
SteveD: is 600-1024 range coming from:

What is that 2nd UDP port used for?
Comment 2 Alan Pevec 2008-06-24 05:57:01 EDT
Raising severity b/c this can happen on any reboot, preventing krb5kdc service
to start!
Workaround could be to avoid using krb4 port by specifying:
 kdc_ports = 88
in /var/kerberos/krb5kdc/kdc.conf

Could an option to disable krb4 be added to ipa-server-install and
/usr/share/ipa/kdc.conf.template modified accordingly?
Comment 3 Simo Sorce 2008-06-25 10:53:15 EDT
Given the fact MIT is finally dropping krb4 in 1.7 anyway, I think we should
really remove any krb4 compat feature from IPA.

So +1 for me.
Comment 4 Scott Haines 2008-07-01 19:33:33 EDT
Per IPA weekly meeting, reassigning to Simo.
Comment 5 Steve Dickson 2008-07-03 15:50:55 EDT
Would it be possible to post instructions on how to
reproduce this problem as well as pointers to the
software needed... 

Comment 6 Simo Sorce 2008-07-03 15:58:56 EDT
the only software needed is a krb5kdc instance, anyway this bug report made us
aware that we were still listening for kerberos 4 requests, something we never
really wanted to support anyway.
So we are fixing this by simply stopping listening on that port at all.
Comment 7 Alan Pevec 2008-07-03 17:04:38 EDT
simplest way to reproduce is to run Steps to Reproduce: 1.
sooner or later rpcbind will pick port 750 (when it gets the right pid)
then yum install krb5-server and service krb5kdc start
Comment 10 Yi Zhang 2008-07-25 15:01:55 EDT
Bug verified. Bug closed

I have a small perl program to listen on 750. and then I run ipa-server-install.
The installation runs through the end without any problem while the perl still
listen on port 750. Therefore it proves the port 750 has been discard by the
errata new bits.

the perl script as below


use IO::Socket;

my $sock = new IO::Socket::INET (
        LocalHost => 'localhost',
        LocalPort => '750',
        Proto => 'tcp',
        Listen => 1,
        Reuse => 1,
) or  die "Could not create socket: $!\n" unless $sock;
print "listen on 750";

my $new_sock = $sock->accept();
        while(<$new_sock>) {
         print $_;
Comment 12 errata-xmlrpc 2008-08-04 14:21:08 EDT
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.


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