DHCP failover doesn't work

[Jan Roehrich]

Hello list,

I'm trying to configure dhcp failover with 2 dhcp servers but it seems
that they won't speak with each other. 
I used the example from dhcpd.conf(5) but there are some error log
messages on both sides.

The primary (which was stand alone before) says: 
vergisstnix dhcpd: failover peer foo: I move from startup to recover
vergisstnix dhcpd: failover: link startup timeout

while the secondary says:
verliernix dhcpd: timeout waiting for failover peer foo
verliernix dhcpd: peer foo: disconnected

My dhcpd.conf files look like that:

-----------------------
failover peer "foo" {
       primary;
       address 137.251.44.6;
       port 519;
       peer address 137.251.44.3;
       peer port 519;
       max-response-delay 60;
       max-unacked-updates 10;
       mclt 240;
       split 128;
}
include "/etc/dhcpd.master";
--------------------


--------------------
failover peer "foo" {
        secondary;
        address 137.251.44.3;
        port 519;
        peer address 137.251.44.6;
        peer port 519;
}                                                      
include "/etc/dhcpd.master";
----------------------

And the dhcpd.master on both machines looks like that:
----------------------
option domain-name "swt.iao.fhg.de";
option domain-name-servers      137.251.44.4, 137.251.36.1,
137.251.36.6;
default-lease-time 604800;
max-lease-time 2419200;
use-host-decl-names off;
ddns-update-style ad-hoc;
                                                                                
subnet 137.251.44.0 netmask 255.255.252.0 {
        option routers          137.251.44.100;
        option subnet-mask      255.255.252.0;
        pool {
                deny dynamic bootp clients;
                failover peer   "foo";
                range           137.251.45.0 137.251.46.254;
        }
}
-----------------------

As you can see I'm using IPs in the differnet "address" parameters. If I
try to use DNS names both servers log "invalid argument" while trying to
connect to each other.

But with tcpdump I can see how both servers communicate trough port 519.

Any ideas?

I can't find enough documentation regarding this so it is not possible
to solve this problem myself.

Greetings Jan

-- 
=============================================
Jan Röhrich
Fraunhofer IAO