Lately, we have been ramping up our OSD in one of our test environments. One of the servers that hosts some of our test VMs sits behind a pretty solid firewall with only the required ports open for Configuration Manager traffic. OSD was rocking and rolling along and then we started to ‘Nomadize’ the Task Sequence. First test and the TS fell over on the first step that attempted to get content (which previously worked).

This one had me scratching my head as I pretty much know Nomad inside and out. It uses the same ports as Configuration Manager when getting content from a Distribution Point. I have seen where proxies have been configured (even for system), but this usually doesn’t break. It just makes it slower than it needs to be since the proxy slows things down. After combing the log, one line in particular caught my eye:

LinkSpeed {url} cannot be calculated (try using AssumedLinkSpeed setting)

I turns out Ping (ICMP) was blocked on the firewall and Nomad was not able to calculate an initial link speed value. On the full client, there is a setting in the registry called AssumedLinkSpeed (referenced in the log). It will use this value instead when it cannot initially reach the DP via ICMP. For this task sequence, we were in WinPE since it was a bare metal build. There is a step in the task sequence actions called Install and Configure Nomad in Windows PE. This step enables Nomad to work in WinPE. As I opened the registry in WinPE, I noticed that AssumedLinkSpeed was missing (and hence the reason for the failure). To correct this, I created a Run Command Line step with the following command directly after each of the Install and Configure Nomad in Windows PE steps:

Step Name: Set Nomad Assumed Link Speed FIX
Command: reg add HKLM\Software\1E\NomadBranch /v AssumedLinkSpeed /t REG_DWORD /d 100 /f

After adding this and rerunning the task sequence is was off and running downloading content. I have submitted a case with the vendor and hopefully it will get fixed in an upcoming hotfix.

Originally posted on https://miketerrill.net/