Fping incompatibility with Freebsd oses about fping

I have completed those tests with different versions of FreeBSD in different networks architectures (with/without vlans,vrrp...). Chatting at Freenode #Zabbix channel other user using FreeBSD have reproduced the same issue.

Clarification on the procedure to reproduce the problem :

First of all, the goal is to use fping command to check an unreachable host_ip availability (this host must be DOWN) LOCATED ON THE LOCAL NETWORK, same subnet (your FreeBSD has an interface and
an IP in this network).

(ps : Using fping with ip located on external/routed network, fping always
works normally, without any error)

Then you have to launch this command 2 or 3 consecutive times from
your box using the SAME non responsive IP (very important, you have to
make the test with the same IP and as soon command is finished start
again 2 or 3 times):

Fping free_ip_address
Fping free_ip_address (do not change ip)
Fping free_ip_adress (do not change ip)

If you follow this procedure you will get something like:

fping 10.0.5.81 ==> 10.0.5.81 is unreachable
fping 10.0.5.81 ==> 10.0.5.81 error while sending ping: Host is down
10.0.5.81 error while sending ping: Host is down
10.0.5.81 error while sending ping: Host is down
10.0.5.81 error while sending ping: Host is down
10.0.5.81 error while sending ping: Host is down
10.0.5.81 error while sending ping: Host is down
10.0.5.81 error while sending ping: Host is down
10.0.5.81 error while sending ping: Host is down

Then pfing will get stuck and if you ctrl-c, it will stop and you will
get the normal fping output : ^C10.0.5.81 is unreachable

The first try will be ok with a normal result, as soon as you will
make a second try you will see the errors.

FreeBSD Fping port maintainer have confirmed this issue.

A suggestion would be a negative caching issue that fping doesn't handle.

FreeBSD Problem Report :
http://www.freebsd.org/cgi/query-pr.cgi?pr=176439

A patch has been submitted by FreeBSD Fping port maintainer (refer http://www.freebsd.org/cgi/query-pr.cgi?pr=176439):

diff -r 830ac78f8d7f files/patch-fping.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/files/patch-fping.c Tue Mar 05 08:53:29 2013 -0400
@@ -0,0 +1,16 @@
+diff -r c564b3055165 src/fping.c
+--- src/fping.c Tue Mar 05 08:13:11 2013 -0400
++++ src/fping.c Tue Mar 05 08:45:33 2013 -0400
+@@ -1572,7 +1572,11 @@

• n = sendto( s, buffer, ping_pkt_size, 0,
• ( struct sockaddr* )&h->saddr, sizeof( FPING_SOCKADDR ) );
  +
  +- if( n < 0 || n != ping_pkt_size )
  ++ if(( n < 0 || n != ping_pkt_size)
  ++#if defined( EHOSTDOWN )
  ++ && errno != EHOSTDOWN
  ++#endif
  ++ )
• {
• if( verbose_flag || unreachable_flag )
• {
  -----BEGIN PGP SIGNATURE-----
  Version: GnuPG v1.4.12 (FreeBSD)

Can anyone validate and integrate if functional.

Thanks