[Dnsmasq-discuss] Problem with TFTP in dnsmasq

Geert Stappers stappers at stappers.nl
Wed Jun 9 07:58:12 UTC 2021

On Tue, Jun 08, 2021 at 08:54:45PM +0000, Brown, Aaron M. wrote:
> Hello all,
> I'm having trouble getting dnsmasq and tftp to work and I'm tearing
> my hair out. I'm hoping someone can potentially hit me with the clue
> by four and point out what dumb thing I'm missing.

Please, more respect for yourself.
You are doing great. Do known that you detected that you are stuck.
It was you who made the step to ask mankind for help.

Short: Be kind enough to respond to this posting.

> In the bigger scope, I'm trying to get PXE booting setup on a server,
> but at the moment before I even get to anything more complicated, I'm
> struggling just to get TFTP to work. I have set up my /etc/dnsmasq.conf
> file as the following:
> interface=bond0
> port=0
> enable-tftp
> tftp-root=/tftp
> log-dhcp
> dhcp-range=<serverIPAddress>,proxy
> dhcp-no-override
> dnsmasq is up and running without errors. I put a simple file in /tftp
> called "test.txt". The /tftp directory has been set to 755 permissions.

And which permissions has file 'test.txt'?

> I then go to client computer and using a tftp client attempt to GET
> the test.txt file but it times out without retrieving the file.

Please explicite that the filename is 'test.txt' for the tftp GET.
( not '/tftp/test.txt' )
> There is no firewall running when I do this on either server or client
> and I can ping from both client and server to each other.


> On the server, I see in a tcpdump of port 69 that the client is making
> RRQ requests. When I look at the status of the dnsmasq service I see:
> Jun 08 16:13:46 <serverName> dnsmasq-tftp[258381]: failed sending /tftp/test.txt to <clientIPAddress>
> There's a similar message in /var/log/syslog as well for dnsmasq-tftp
> failing to send the file.
> I've been pouring over the docs/man pages and the sample .conf file,
> but I'm clearly not understanding what I'm missing.

It is surely an interresting problem.

> Anyone have any ideas?

Only a wild guess:
Dnsmasq process has NOT the privelege to send.

I don't know if such thing exists, but I'm thinking "capabilities".
Capabilities as in https://manpages.debian.org/buster/manpages/capabilities.7.en.html

> I've searched the web for similar problems, but I haven't been able
> to find anything that resembles my situation. Usually people seem to
> have issues after this point with what TFTP is passing out, not just
> getting TFPT up and running.


Acknowledge on "your question is very valid".
Otherwise I would have ignored it. Backgrond information
at http://www.catb.org/~esr/faqs/smart-questions.html

> Server OS: Ubuntu 20.04 Server
> Client OS: Ubuntu 20.04 Desktop
> Aaron M Brown
> Engineering College Computing
> Desktop Administrator
> NI1013A - 419.530.8022

Geert Stappers

Dnsmasq tftp works for me ...
Silence is hard to parse

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