constantly repeated DHCPINFORM and DHCPACK messages in /var/log/messages

[Matt Shaffer_1]

My DHCP server is running RHEL3U4. My clients are either Win thin clients or Win PCs. I see repeated DHCPINFORM and DHCPACK messages in /var/log/messages (see below) and I don't know why. My dhcpd.conf file seems right to me. Please let me know what else I can provide. As always, thank you!

Jul 10 13:20:31 1920 dhcpd: DHCPINFORM from 10.4.22.216 via eth0
Jul 10 13:20:31 1920 dhcpd: DHCPACK to 10.4.22.216
Jul 10 13:20:32 1920 dhcpd: DHCPINFORM from 10.4.22.214 via eth0
Jul 10 13:20:32 1920 dhcpd: DHCPACK to 10.4.22.214
Jul 10 13:21:01 1920 dhcpd: DHCPINFORM from 10.4.22.212 via eth0
Jul 10 13:21:01 1920 dhcpd: DHCPACK to 10.4.22.212
Jul 10 13:21:06 1920 dhcpd: DHCPINFORM from 10.4.22.212 via eth0
Jul 10 13:21:06 1920 dhcpd: DHCPACK to 10.4.22.212
Jul 10 13:21:26 1920 dhcpd: DHCPINFORM from 10.4.22.215 via eth0
Jul 10 13:21:26 1920 dhcpd: DHCPACK to 10.4.22.215

[Steven E. Protter · Accepted solution]

Shalom,

These messages are informational.

It merely notes that the address is being handed out.

It appears that this is normal activity to me though one address appears to be repeated.

It might help to see the dhcpd.conf file

SEP

[Ivan Ferreira]

DHCPINFORM: If a client has obtained a network address through some other means or has a manually configured IP address, a client workstation may use a DHCPINFORM request message to obtain other local configuration parameters, such as the domain name and Domain Name Servers (DNSs). DHCP servers receiving a DHCPINFORM message construct a DHCPACK message with any local configuration parameters appropriate for the client without allocating a new IP address. This DHCPACK will be sent unicast to the
client.

Where those IP address listed there manually configured? Probably you need to complete the configuration for TCP/IP domain name, domain name server, netbios server, etc.

[Matt Shaffer_1]

All of the IPs that are sending DHCPINFORM packets also have leases in /var/lib/dhcp/dhcpd.leases so they're getting their address from DHCP. I've attached the dhcpd.conf file. Thanks

[Matt Shaffer_1]

I found this regarding DHCPINFORM:

"The 'inform' messages are used when the client already has an address
and wants to extend the lease or get additional info."

I have approx 400 remote dhcp servers each serving up addresses for the local workers at the remote sites. Now that I'm starting to look at this, I'm finding the same behavior at each site. Clients that already have a DHCP address are sending DHCPINFORM packets to the server. Maybe this is normal behavior? I just feel that this could be tweaked a little. Thoughts? I've attached a file that contains a client entry in dhcpd.leases and the messages in /var/log/messages that pertain to this client. THANK YOU

[Matt Shaffer_1]

no idea