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HTTP and HTTPS FQDN Connection Failures On iDRAC9 Firmware Version

Summary: The Dell iDRAC9 firmware version blocks HTTP and HTTPS access through the Fully Qualified Domain Name (FQDN) when the FQDN. It is not defined as the iDRAC Remote Access Controller (RAC) name. ...

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The Dell Integrated Dell Remote Access Controller 9 (iDRAC9) firmware version introduced HTTP and HTTPS connection changes. These changes may impact user connections when specifying a Fully Qualified Domain Name (FQDN) address. Due to these changes, iDRAC9 users may encounter connection errors, redirection, or '400 - Bad Request' errors. These connection sightings occur when the specified FQDN does not match the iDRAC 'DNSRacName' or 'DNSDomainName' values.

Browser Error Example:

Mozilla HTTPS header error
Figure 1: Mozilla HTTPS header error Curl Error Example:

	root@rhel7-vm:~$ curl -k
	<!DOCTYPE html>
	    <title>Bad Request</title>
	    <link rel="shortcut icon" href="data:image/x-icon;," type="image/x-icon">
	    <h2>Access Error: 400 -- Bad Request</h2>


The webserver in iDRAC9 firmware version enforces an HTTP and HTTPS Host Header check by default.


NOTE: To see images of the process used to configure the DNS, iDRAC Name, and Static DNS Domain Name correctly in the user interface see: How to configure the Integrated Dell Remote Access Controller 9 (iDRAC9) with Lifecycle Controller network settings?

By default, the iDRAC9 checks the HTTP and HTTPS Host Header and compares to the defined 'DNSRacName' and 'DNSDomainName'. When the values do not match, the iDRAC refuses the HTTP and HTTPS connection. In iDRAC9, this Host Header enforcement can be disabled with the following RACADM command.


#Disable host header check

racadm set idrac.webserver.HostHeaderCheck 0
Note: Only set the HostHeaderCheck value to '0' when a manual Host Record exists within the DNS environment.

When HTTP and HTTPS Host Header check is enabled (more secure), iDRAC can be accessed using the IPv4/IPv6 address, the RAC Name and the defined iDRAC FQDN (DNSRacName.DNSDomainName). If the end-user is accessing with hostnames that the iDRAC may not be aware of (such as manual DNS entries added in DNS records), iDRAC9 firmware version introduced a new attribute 'ManualDNSEntry'. This new setting can be updated with up to four IP addresses and host names/FQDNs to provide an allow-list of Host Headers. This ensures that incoming requests are not dropped when the HTTP and HTTPS Host Header carries one of the entries in the 'ManualDNSEntry' setting.

# Add manual entry to allow list

racadm set idrac.webserver.ManualDNSEntry

racadm set idrac.webserver.ManualDNSentry,

This additional configuration is required in cases such as when:

  • End user is using manual DNS configuration to access iDRAC (Manual DNS Host Record)
  • Subject Alternative Name/Wild card certificate is used to access the iDRAC
  • Accessing iDRAC using host IP address directly (usingISM)
Note: To resolve ISM connection problems, disabling the host header check feature is the only mitigation. Manual DNS Entries do not resolve ISM connections.

Article Properties

Affected Product
iDRAC9 - 5.xx Series, PowerEdge XR2, Poweredge C4140, PowerEdge C6420, PowerEdge C6520, PowerEdge C6525, PowerEdge C6615, PowerEdge C6620, PowerEdge FC640, PowerEdge HS5610, PowerEdge HS5620, PowerEdge M640, PowerEdge M640 (for PE VRTX) , PowerEdge MX740C, PowerEdge MX750c, PowerEdge MX760c, PowerEdge MX840C, PowerEdge R240, PowerEdge R250, PowerEdge R340, PowerEdge R350, PowerEdge R440, PowerEdge R450, PowerEdge R540, PowerEdge R550, PowerEdge R640, PowerEdge R6415, PowerEdge R650, PowerEdge R650xs, PowerEdge R6515, PowerEdge R6525, PowerEdge R660, PowerEdge R660xs, PowerEdge R6615, PowerEdge R6625, PowerEdge R740, PowerEdge R740XD, PowerEdge R740XD2, PowerEdge R7415, PowerEdge R7425, PowerEdge R750, PowerEdge R750XA, PowerEdge R750xs, PowerEdge R7515, PowerEdge R7525, PowerEdge R760, PowerEdge R760XA, PowerEdge R760xd2, PowerEdge R760xs, PowerEdge R7615, PowerEdge R7625, PowerEdge R840, PowerEdge R860, PowerEdge R940, PowerEdge R940xa, PowerEdge R960, PowerEdge T140, PowerEdge T150, PowerEdge T340, PowerEdge T350, PowerEdge T440, PowerEdge T550, PowerEdge T560, PowerEdge T640, PowerEdge XE2420, PowerEdge XE7420, PowerEdge XE7440, PowerEdge XE8545, PowerEdge XE8640, PowerEdge XE9680, PowerEdge XR11, PowerEdge XR12, PowerEdge XR4510c, PowerEdge XR4520c, PowerEdge XR5610, PowerEdge XR7620, PowerEdge XR8610t, PowerEdge XR8620t ...
Last Published Date

06 Jun 2024



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