DHCP error

[benningtonr]

No DHCPOFFERs were received.

command = check_dhcp!

Any Ideas?

[scottwilkerson]

Is there an active DHCP server on your network?

Does the DHCP server have available IP's to allocate?

[benningtonr]

Yes and yes

[scottwilkerson]

it could be a firewall issue. To test you can do

Code: Select all

cd /usr/local/nagios/libexec
service iptables stop
./check_dhcp
service iptables start

[benningtonr]

I am guessing this is ok?

[root@helpdesk27 libexec]# service iptables stop
iptables: Flushing firewall rules: [ OK ]
iptables: Setting chains to policy ACCEPT: filter [ OK ]
iptables: Unloading modules: [ OK ]
[root@helpdesk27 libexec]# ./check_dhcp
OK: Received 1 DHCPOFFER(s), max lease time = 0 sec.
[root@helpdesk27 libexec]# service iptables start
iptables: Applying firewall rules: [ OK ]
[root@helpdesk27 libexec]#

[lmiltchev]

Yes, this was a firewall issue. It's working now:

[root@helpdesk27 libexec]# ./check_dhcp
OK: Received 1 DHCPOFFER(s), max lease time = 0 sec.

I believe you need to open UDP ports 67 & 68 in iptables.

[benningtonr]

i need to open them on the nagios?

[benningtonr]

[root@helpdesk27 ~]# iptables --list
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT icmp -- anywhere anywhere
ACCEPT all -- anywhere anywhere
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ssh
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:http
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:https
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited

Chain FORWARD (policy ACCEPT)
target prot opt source destination
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

[scottwilkerson]

i need to open them on the nagios?

Yes.

Run

Code: Select all

iptables -I INPUT -i eth0 -p udp --dport 67:68 --sport 67:68 -j ACCEPT

[benningtonr]

Great, that worked, thank you