I am setting up a Serva server for Ubuntu, per these instructions, and I can't seem to get Ubuntu to load on my client machine. The config file (from that link, which says it has been tested on Ubuntu 14.04.1 desktop):

asset    = Ubuntu LTS 14.04 Desktop Live
platform = amd64
kernel   = NWA_PXE/$HEAD_DIR$/casper/vmlinuz
append   = showmounts toram root=/dev/cifs initrd=NWA_PXE/$HEAD_DIR$/casper/initrd.lz,NWA_PXE/$HEAD_DIR$/casper/INITRD_N11.GZ boot=casper netboot=cifs nfsroot=//$IP_BSRV$/NWA_PXE_SHARE/$HEAD_DIR$ NFSOPTS=-ouser=serva,pass=avres,ro ip=dhcp ro

I changed the NFSOPTS=-ouser=serva,pass=avres part to NFSOPTS=-o user=theserver, password=p4ssw0rd because it had initially complained that -ouser was a bad option. theserver and p4ssw0rd are the username and password of the user account on the server machine (Windows 7). I have also shared the appropriate Serva folder, per the instructions.

Could someone take a look and see if it's a problem with my config file? Or could someone with more experience tell me what I'm doing wrong?

  • What is a "Serva"? You should clarify that soon - I first thought it is a very wrong spelling of server, hinting to a very low quality question... – Volker Siegel Aug 12 '14 at 20:37
  • @VolkerSiegel ahhh...that is a good point. thanks. – yiwei Aug 12 '14 at 22:29
  • For a Windows 10 SMB share on my domain sec=ntlm needed to mount the share also i used domain=mydomain in ServaAsset.inf. – Darren Cayley Oct 6 '17 at 10:46

I too was facing cifs share access issue while network booting via Serva server. After much trials i realized that the username required domain as well since my Network share was hosted on a domain joined machine. Based on suggestions via internet, i was able to network boot successfully by appending text "domain=" to the NFSOPTS param in the ServaAsset.inf. The NFSOPTS looked like following for me:



I had exactly the same problem today.

The problem occurred because the initial core Linux system (as it was booting) was unable to log on to the NWA_PXE_SHARE on my Windows 10 PC - Windows 10 has tougher security for shares than previous versions of Windows.

My solution:

  1. I added sec=ntlm to the NFSOPTS in ServaAsset.inf. This revealed an "access denied" error instead of the bad parameter or bad option error which is a red herring. The bad option error was reported because when the cifs logon fails, it then tries to access an NFS share which does not accept -ouser=xxx.

  2. On the Windows 10 machine I made sure that the "serva" user had explicit read permissions on the "C:\SERVA_REPO\NWA_PXE" folder AND that the "serva" user had explicit sharing permissions set for the NWA_PXE_SHARE share.

Then it worked. I arrived at this conclusion by testing the share from another (weaker) operating system which also worked.

  • Serva troubleshooting section vercot.com/~serva/an/NonWindowsPXE3.html#troubleshooting describes the server side parameters and the client options in order to avoid lowering the security more than necessary. – Pat Dec 5 '17 at 22:11
  • Most default linux infs actually ship with that security protocol already. I think that's kind of begging for problems though (just like I, for one, had to reenable SMB 1.0 server to make it work) at the end of the day. – mirh Nov 20 '19 at 23:39

For me adding only 'sec' didin't resolve my problem, after debugging, i found that i need vers too:

  • vers=1.0 appeared as a new requirement on Ubuntu 17.10 Live, never before – Pat Dec 5 '17 at 22:07

you have to read Serva instructions. i.e. Serva considers that the NWA_PXE_SHARE has a user with minimally reading access called serva with a password avres then you get


in your case that part of the line should be


what you did adding a space after -o is wrong.

if initially the booting says that the -ouser option is not recognized you either.

  1. didn't create the NWA_PXE_SHARE correctly
  2. didn't download/copy INITRD_N11 correctly

bottom line: follow Serva instructions to the letter and you will not fail.

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