I am having a problem where by it can take up to 30 seconds to get an IP address on our Windows 7 Enterprise SP1 32 Bit PCs. The DHCP server is on a Windows 2008 64 Bit server. We are using multiple Cisco Layer 3 switches with DHCP helper addresses. Event Log Shows - Ack Receive Timeout has happened in the Interface Id 13 Event ID 5719 and event ID 1129 may be logged when a non-Microsoft DHCP Relay Agent is used (<//span>http://support.microsoft.com/kb/2459530) sums up the problem but hotfix did not work. I tried to follow the manual instructions but could not follow them. Creating the missing registry Keys did not seem to make sense. If anyone has any advise please let me know Thanks <//span>

1. Does this time lag really matter? (For very short lease time it could...) 2. Check logs on Cisco devices and catch traffic by network monitor. Rgds Milos

1. Does this time lag really matter? (For very short lease time it could...) 2. Check logs on Cisco devices and catch traffic by network monitor. Rgds Milos

Hi , This problem may occur if you have all of the following: Using a DHCP reply to forward DHCP requests (e.g. using VLANs and an IP helper on the router to forward DHCP requests)Windows 7 clientsWindows Firewall Public Profile turned on (default configuration - all profiles)DhcpConnForceBroadcastFlag = 0 (Default for Windows 7) The problem occurs when your client has to access the DHCP server via a DHCP relay, such as a router or switch and the DhcpConnForceBroadcastFlag registry key is still set to the default(0). In this situation, the client sends out a broadcasts requesting an IP address, the DHCP relay forwards the request to the DHCP server, the DHCP server sends the reply(ACK reply) to the relay and the DHCP relay sends a unicast reply to the client. If the Public profile is turned on in the Windows Firewall (on by default) then the ACK reply is dropped by the windows 7 client firewall . Using Netmon you can see the correct traffic on the wire, but the client is not accepting the ACK packet. Also, check the answers which provided by Wilson Jia and Arkturas in this link and see if it can help. http://social.technet.microsoft.com/Forums/en/windowsserver2008r2general/thread/044e57eb-47a4-4988-92b5-faa68ad58025 Tracy Cai TechNet Community Support

Hi , This problem may occur if you have all of the following: Using a DHCP reply to forward DHCP requests (e.g. using VLANs and an IP helper on the router to forward DHCP requests)Windows 7 clientsWindows Firewall Public Profile turned on (default configuration - all profiles)DhcpConnForceBroadcastFlag = 0 (Default for Windows 7) The problem occurs when your client has to access the DHCP server via a DHCP relay, such as a router or switch and the DhcpConnForceBroadcastFlag registry key is still set to the default(0). In this situation, the client sends out a broadcasts requesting an IP address, the DHCP relay forwards the request to the DHCP server, the DHCP server sends the reply(ACK reply) to the relay and the DHCP relay sends a unicast reply to the client. If the Public profile is turned on in the Windows Firewall (on by default) then the ACK reply is dropped by the windows 7 client firewall . Using Netmon you can see the correct traffic on the wire, but the client is not accepting the ACK packet. Also, check the answers which provided by Wilson Jia and Arkturas in this link and see if it can help. http://social.technet.microsoft.com/Forums/en/windowsserver2008r2general/thread/044e57eb-47a4-4988-92b5-faa68ad58025 Tracy Cai TechNet Community Support

Thanks. For the replies. The short lag time in getting the IP address means when we map our drives using batch files they have a red x on them. If you double click on them the drives map ok but does generate a few support calls. I have tried several articles which talk about DhcpConnForceBroadcastFlag and even ran a windows hotfix but did not seem to do much. Will try the article Tracy mentioned and get back to you

Thanks. For the replies. The short lag time in getting the IP address means when we map our drives using batch files they have a red x on them. If you double click on them the drives map ok but does generate a few support calls. I have tried several articles which talk about DhcpConnForceBroadcastFlag and even ran a windows hotfix but did not seem to do much. Will try the article Tracy mentioned and get back to you

Hi , I am currently standing by for an update from you and would like to know how things are going. If you have any feedback, please let us know.Tracy Cai TechNet Community Support

Hi , I am currently standing by for an update from you and would like to know how things are going. If you have any feedback, please let us know.Tracy Cai TechNet Community Support