[Lubuntu] TFTP Open Timeout error (or Transfer timed out error)

John Hupp lubuntu at prpcompany.com
Thu Nov 15 15:46:15 UTC 2012


I'm trying to troubleshoot an LTSP (the new LTSP-PNP) client boot 
problem under Quantal.

The problem is that the LTSP client, after successfully getting DHCP 
assignments, fails to download the pxelinux boot image.  It reports 
"PXE-E32 TFTP open timeout."

I can also run this on the server itself to get a similar failure:
$ cd /tmp
$ tftp 192.168.1.102 -v -m binary -c get ltsp/i386/pxelinux.0 mode set 
to octet
Connected to 192.168.1.102 (192.168.1.102), port 69
getting from 192.168.1.102:/var/lib/tftpboot/ltsp/i386/pxelinux.0 to 
pxelinux.0 [octet]
Transfer timed out.

A critical note: This is using the default network-manager to configure 
the network interface (using the default DHCP configuration).  
Apparently network-manager also runs or works with dnsmasq, which 
provide DHCP and TFTP servers.

When I had TFTP and DHCP errors booting the client under LTSP5 and 
Precise, I learned that the usual work-around was to configure the 
network interface(s) via /etc/network/interfaces.  I think this solved 
some sort of a timing problem with the relevant services during bootup.

But that approach is apparently deprecated under Quantal and LTSP-PNP.  
In fact, I can use that approach to get the client to boot successfully, 
but it introduces a new problem on server and client: DNS resolution 
fails.  This happens because the use of /etc/network/interfaces uses, I 
think, ifup (or something related) to configure network interfaces 
instead of network-manager, but now network-manager works with dnsmasq 
to provide DNS resolution.

I can fix the DNS resolution problem by creating 
/etc/resolvconf/resolv.conf.d/tail with contents:
nameserver (my nameserver 1)
nameserver (my nameserver 2)

But instead of patching up the old approach, I'd like to get the new 
approach working right.  But I don't know enough to move ahead with 
troubleshooting, and no one on the LTSP mail list has been able to put a 
finger on the problem yet, so I'm putting it in front of a different set 
of eyes here.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ubuntu.com/archives/lubuntu-users/attachments/20121115/82533f71/attachment.html>


More information about the Lubuntu-users mailing list