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July 9th, 2025 07:09
New R6725 iDRAC won’t save the gateway it gets from DHCP
Hi everyone,
I’ve hit an odd network glitch on several brand-new PowerEdge R6725 servers:
Firmware: iDRAC 10 v1.20.50.50 (latest public build)
DHCP: ordinary scope on an untagged switch port
Mode: dedicated iDRAC NIC
What I expect
When iDRAC is set to DHCP, it should pick up four things from the server:
IP address
Subnet mask
Default gateway
DNS servers
What actually happens
It grabs the IP and subnet mask just fine.
It drops the gateway—iDRAC shows 0.0.0.0 instead of the router the DHCP server offered.
Because of that, the controller can’t be reached from outside its tiny /30 network.
Example after a lease:
# racadm get iDRAC.IPv4[Key=iDRAC.Embedded.1#IPv4.1]#Address=10.0.0.230DHCPEnable=Enabled#DNS1=192.0.2.53#DNS2=198.51.100.53#DNS3=0.0.0.0DNSFromDHCP=DisabledEnable=Enabled#Gateway=0.0.0.0#Netmask=255.255.255.252StaticAddress=10.0.0.230StaticDNS1=192.0.2.53StaticDNS2=198.51.100.53StaticDNS3=0.0.0.0StaticGateway=10.0.0.229StaticNetmask=255.255.255.252Older Dell models on the same DHCP scope work perfectly, and if I set a static address on the R6725 the gateway sticks, so the issue seems limited to this iDRAC build.
Things I already tried
Updated from 1.20.25.00 → 1.20.50.50 – no change
Tested /31 and /30 subnets – same result
Compared packets – DHCP ACK clearly includes the correct router option
Static config – works, but we’d rather keep everything on DHCP
What I need
Could someone from Dell confirm if this is a known bug, or point me to a hot-fix / newer build that keeps the gateway? I can supply a packet capture, racadm dump, and service tag if needed.
Thanks!
rudniev.vv
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July 17th, 2025 12:56
I finally tracked down why my new PowerEdge R6725 iDRAC kept showing a gateway of 0.0.0.0 even though DHCP was offering the correct router.
What’s going on
My DHCP server sends both DHCP Option 3 (Router) and Option 121 (Classless Static Routes). The Option 121 payload listed a few specific routes but did not include a default route. According to RFC 3442, if a DHCP client supports Classless Static Routes and receives both options, it must ignore Option 3. So the iDRAC throws away the router from Option 3; with no default in Option 121, it ends up with gateway 0.0.0.0.
Behavior difference vs older iDRAC
On older Dell generations (earlier iDRAC), the controller effectively ignored Option 121 and still used the router from Option 3, so everything “worked” and we never noticed the bad Option 121 encoding. The new iDRAC build on my R6725 appears to actually honor RFC 3442, which exposes the misconfig.
Repro summary
DHCP sends only Option 3 → gateway installs correctly.
DHCP sends Option 3 + Option 121 without default → gateway shows 0.0.0.0.
DHCP sends Option 3 + Option 121 with default route (0.0.0.0/0,gateway-ip) → gateway installs correctly.
What to do
Best fix: include the default route inside Option 121 (put it first in the list). Example syntax (varies by DHCP implementation):
dhcp-option=121,0.0.0.0/0,192.0.2.1,198.51.100.0/24,192.0.2.2
That preserves any extra static routes and keeps standards compliance.
Fallback / workaround: stop sending Option 121 to iDRAC if you don’t actually need to push classless routes to the management network. You can key off the iDRAC vendor class ID (Option 60 reports “iDRAC”) in many DHCP servers and hand out a simpler option set.
I suspect other folks may hit the same thing when rolling newer servers into older DHCP scopes that were never cleaned up. If your iDRAC shows 0.0.0.0 for the gateway even though DHCP looks right, check whether you’re also sending Option 121 without a default route. Hope this saves someone some time.
(edited)
DELL-Erman O
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July 9th, 2025 13:17
Hello,
please Using "racadm getniccfg" to confirm that the gateway is being received. If the gateway is missing, try
try to reboot via "racadm racreset" if continue then resetting to factory defaults via "racadm racresetcfg" this way you lose any setting you setup.
Hope that helps!
rudniev.vv
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July 9th, 2025 14:12
Thanks, @DELL-Erman O.
I’d already tried both:
racadm racreset
racadm racresetcfg (factory defaults)
The behaviour is unchanged.
(The static IP is deliberately different so I can verify that the lease really comes from DHCP, not from any cache.)
Still no gateway - any other ideas?
DELL-Erman O
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July 9th, 2025 14:17
@rudniev.vv As I have seen, you have the latest IDRAC version, so you may want to try a former version with a downgrade. Seeing it is still the same or not. I couldn't find a release note about how to fix it.
DELL-Erman O
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July 17th, 2025 13:29
Thanks for your valuable feedback, have a good one!