<div class="post-text">
<p>I use ISC DHCP version 4.1.1 on Debian GNU/Linux on both servers.
I tried to solve the following problem using various versions of ISC DHCP but it remained the same.</p>
<p>My configuration for failover between two servers on different subnets is:</p>
<pre><code>#-----------------------------------------------
# Primary Server
#-----------------------------------------------
authoritative;
default-lease-time 900;
max-lease-time 1800;
option domain-name "<a href="http://foo.com">foo.com</a>";
option domain-name-servers 10.12.0.254;
failover peer "foo" {
primary;
address 10.12.0.254;
port 647;
peer address 10.10.10.12;
peer port 647;
max-response-delay 30;
max-unacked-updates 10;
load balance max seconds 3;
mclt 1800;
split 128;
}
subnet 10.12.0.0 netmask 255.255.0.0 {
pool {
failover peer "foo";
range 10.12.10.0 10.12.112.0;
range 10.12.112.12 10.12.255.254;
deny dynamic bootp clients;
}
option routers 10.12.0.254;
option subnet-mask 255.255.0.0;
option broadcast-address 10.12.255.255;
}
#-----------------------------------------------
# Secondary Server
#-----------------------------------------------
authoritative;
default-lease-time 900;
max-lease-time 1800;
option domain-name "<a href="http://foo.com">foo.com</a>";
option domain-name-servers 10.12.0.254;
failover peer "foo" {
secondary;
address 10.10.10.12;
port 647;
peer address 10.12.0.254;
peer port 647;
max-response-delay 30;
max-unacked-updates 10;
load balance max seconds 3;
}
subnet 10.12.0.0 netmask 255.255.0.0 {
pool {
failover peer "foo";
range 10.12.10.0 10.12.112.0;
range 10.12.112.12 10.12.255.254;
deny dynamic bootp clients;
}
option routers 10.12.0.254;
option subnet-mask 255.255.0.0;
option broadcast-address 10.12.255.255;
}
subnet 10.10.10.0 netmask 255.255.255.240 {
}
</code></pre>
<p>IP helper (aka UDP helper) and DHCP relay is enabled on router that
connects the network of the primary server with the network of the
secondary server
I can ping and ssh from one server to the other and back.</p>
<p>When I start the dhcpd service on both servers they fail to balance their leases.</p>
<p>I paste a sample of the logs of both servers</p>
<p>Primary Server</p>
<pre><code>Sep 19 10:31:11 primary dhcpd: failover peer foo: I move from recover to startup
Sep 19 10:31:11 primary dhcpd: failover peer foo: I move from startup to recover
Sep 19 10:31:11 primary dhcpd: Sent update request all message to foo
Sep 19 10:31:20 primary dhcpd: peer foo: disconnected
Sep 19 10:31:22 primary dhcpd: failover peer foo: peer moves from recover-done to recover-done
Sep 19 10:31:22 primary dhcpd: failover peer foo: peer moves from recover-done to recover-done
Sep 19 10:31:45 primary dhcpd: DHCPINFORM from 10.12.181.177 via eth1
Sep 19 10:31:45 primary dhcpd: DHCPACK to 10.12.181.177 (00:17:42:c0:e3:ce) via eth1
Sep 19 10:32:45 primary dhcpd: DHCPDISCOVER from 00:16:d3:e5:3a:3c (PC1) via eth1: not responding (recovering)
Sep 19 10:32:46 primary dhcpd: DHCPINFORM from 10.12.181.177 via eth1
Sep 19 10:32:46 primary dhcpd: DHCPACK to 10.12.181.177 (00:17:42:c0:e3:ce) via eth1
Sep 19 10:32:49 primary dhcpd: DHCPDISCOVER from 00:16:d3:e5:3a:3c (PC1) via eth1: not responding (recovering)
Sep 19 10:32:57 primary dhcpd: DHCPDISCOVER from 00:16:d3:e5:3a:3c (PC1) via eth1: not responding (recovering)
Sep 19 10:33:13 primary dhcpd: DHCPDISCOVER from 00:19:99:95:41:99 (PC2) via eth1: not responding (recovering)
Sep 19 10:33:13 primary dhcpd: DHCPDISCOVER from 00:16:d3:e5:3a:3c (PC1) via eth1: not responding (recovering)
Sep 19 10:33:17 primary dhcpd: DHCPDISCOVER from 00:19:99:95:41:99 (PC2) via eth1: not responding (recovering)
Sep 19 10:33:25 primary dhcpd: DHCPDISCOVER from 00:19:99:95:41:99 (PC2) via eth1: not responding (recovering)
Sep 19 10:33:41 primary dhcpd: DHCPDISCOVER from 00:19:99:95:41:99 (PC2) via eth1: not responding (recovering)
</code></pre>
<p>Secondary Server</p>
<pre><code>Sep 19 10:31:11 secondary dhcpd: Update request all from foo: sending update
Sep 19 10:31:23 secondary dhcpd: Wrote 22 leases to leases file.
Sep 19 10:31:23 secondary dhcpd: failover peer foo: I move from recover-done to startup
Sep 19 10:31:23 secondary dhcpd: failover peer foo: I move from startup to recover-done
Sep 19 10:31:45 secondary dhcpd: DHCPINFORM from 10.12.181.177 via 10.12.0.1
Sep 19 10:31:45 secondary dhcpd: DHCPACK to 10.12.181.177 (00:17:42:c0:e3:ce) via eth0
Sep 19 10:32:45 secondary dhcpd: DHCPDISCOVER from 00:16:d3:e5:3a:3c via <a href="http://10.12.0.1">10.12.0.1</a>: not responding (recover done)
Sep 19 10:32:46 secondary dhcpd: DHCPINFORM from 10.12.181.177 via 10.12.0.1
Sep 19 10:32:46 secondary dhcpd: DHCPACK to 10.12.181.177 (00:17:42:c0:e3:ce) via eth0
Sep 19 10:32:49 secondary dhcpd: DHCPDISCOVER from 00:16:d3:e5:3a:3c via <a href="http://10.12.0.1">10.12.0.1</a>: not responding (recover done)
Sep 19 10:32:57 secondary dhcpd: DHCPDISCOVER from 00:16:d3:e5:3a:3c via <a href="http://10.12.0.1">10.12.0.1</a>: not responding (recover done)
Sep 19 10:33:13 secondary dhcpd: DHCPDISCOVER from 00:19:99:95:41:99 via <a href="http://10.12.0.1">10.12.0.1</a>: not responding (recover done)
Sep 19 10:33:13 secondary dhcpd: DHCPDISCOVER from 00:16:d3:e5:3a:3c via <a href="http://10.12.0.1">10.12.0.1</a>: not responding (recover done)
Sep 19 10:33:17 secondary dhcpd: DHCPDISCOVER from 00:19:99:95:41:99 via <a href="http://10.12.0.1">10.12.0.1</a>: not responding (recover done)
Sep 19 10:33:25 secondary dhcpd: DHCPDISCOVER from 00:19:99:95:41:99 via <a href="http://10.12.0.1">10.12.0.1</a>: not responding (recover done)
Sep 19 10:33:41 secondary dhcpd: DHCPDISCOVER from 00:19:99:95:41:99 via <a href="http://10.12.0.1">10.12.0.1</a>: not responding (recover done)
Sep 19 10:34:46 secondary dhcpd: DHCPDISCOVER from 00:1a:4b:45:3a:2f via <a href="http://10.12.0.1">10.12.0.1</a>: peer holds all free leases
Sep 19 10:34:51 secondary dhcpd: DHCPDISCOVER from 00:1a:4b:45:3a:2f via <a href="http://10.12.0.1">10.12.0.1</a>: peer holds all free leases
Sep 19 10:34:59 secondary dhcpd: DHCPDISCOVER from 00:1a:4b:45:3a:2f via <a href="http://10.12.0.1">10.12.0.1</a>: peer holds all free leases
Sep 19 10:35:16 secondary dhcpd: DHCPDISCOVER from 00:1a:4b:45:3a:2f via <a href="http://10.12.0.1">10.12.0.1</a>: peer holds all free leases
Sep 19 10:38:28 secondary dhcpd: DHCPDISCOVER from 00:16:d3:e5:3a:3c via <a href="http://10.12.0.1">10.12.0.1</a>: not responding (recover done)
Sep 19 10:38:32 secondary dhcpd: DHCPDISCOVER from 00:16:d3:e5:3a:3c via <a href="http://10.12.0.1">10.12.0.1</a>: not responding (recover done)
</code></pre>
<p>I don't seem to have the load balance log lines so I don't think leases balancing is happening...</p>
<pre><code>Sent update request all message to foo
Update request all from foo: sending update
</code></pre>
<p>Balancing process seems stuck on the two lines above</p>
<p>If I shut down the DHCPD daemon on one server the peer doesn't seem to take over even if it detects that other peer is down</p>
<p>How can I fix this problem? </p>
<p>Thank you in advance (and sorry for my bad English) :-)</p>
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