Details
Description
According to the EtherNet/IP specification, the DHCP client must be restarted in case of link loss/up.
This means that the DHCP client needs to start over and send a DISCOVER message to the DHCP server.
(CIP Volume 2, Edition 1.23, Figure 5-4.1 Diagram Showing the Behavior of the TCP/IP Object)
Currently, the DHCP client goes into the state "REBOOTING" where it issues a DHCP REQUEST frame to the DHCP server in order to let the DHCP server check whether the IP address is still allowed to be used.
In addition, during the state "REBOOTING" it happens that DHCP DISCOVER/REQUEST frames are sent with source IP address != 0.0.0.0 (IP header), which is wrong. The soruce IP address is expected to be 0.0.0.0 in that case.
Excerpt from DHCP RFC 2131 (chapter 4.1 Constructing and sending DHCP messages):
"DHCP messages broadcast by a client prior to that client obtaining its IP address must have the source address field in the IP header set to 0."
|
Attachments
Issue Links
- relates to
-
PSLWIP-232 [ACD] In DHCP mode: After link loss/up event, the device does not wait for a DHCP server response before probing the IP address
- Closed