TFTP not working on F15 as well as updated F14

[Aaron Gray]

On 12 October 2011 19:30, Tom Callaway <tcallawa at redhat.com> wrote:

> Okay. Your configurations are the default configs (with the notable
> exception of enabling the xinetd.d/tftp service).
>
> On my x86_64 laptop running Fedora 16, with iptables reasonably normal,
> I installed "tftp" and "tftp-server", and changed "disable = yes" to
> "disable = no" in /etc/xinetd.d/tftp. Then, I ran:
>
>  service xinetd restart
>
> Next, I put a dummy file in /var/lib/tftpboot:
>
> echo "Hello, Fedora." > /var/lib/tftpboot/hello.txt
>
> Then, I tested a tftp connection across the loopback:
>
> [spot at pterodactyl ~]$ tftp -v localhost
> Connected to pterodactyl (127.0.0.1), port 69
> tftp> get hello.txt
> getting from pterodactyl:hello.txt to hello.txt [netascii]
> Received 16 bytes in 0.0 seconds [44990 bit/s]
> tftp> quit
> [spot at pterodactyl ~]$ cat hello.txt
> Hello, Fedora.
>
> Okay, that works. I'd be a bit worried if it didn't. :)
>

Yeah this is the point where it is not working for me.


>
> Next, I tried to connect from a F-14 x86_64 machine on the same network
> (actually connected to the same switch too), and that worked fine:
>
> [spot at treefrog ~]$ tftp -v pterodactyl
> Connected to pterodactyl (XX.XX.XX.XX), port 69
> tftp> get hello.txt
> getting from pterodactyl:hello.txt to hello.txt [netascii]
> Received 16 bytes in 0.0 seconds [18910 bit/s]
> tftp>
>

My F15 laptop works fine local and remote. But I need my F15 server to do
PXE as a router to the internet.


>
> Now, I did notice a failure when I was trying to connect to the server
> from a VM on that separate machine. From the server logs:
>
> Oct 12 14:10:22 pterodactyl in.tftpd[8609]: tftpd: read(ack): Connection
> refused
>
> The client would connect, but it would not download any files.
>
> [spot at f15 ~]$ tftp -v pterodactyl
> Connected to pterodactyl (XX.XX.XX.XX), port 69
> tftp> get hello.txt
> getting from pterodactyl:hello.txt to hello.txt [netascii]
> Transfer timed out.
>
> The trick to getting the VM working was to run this command on the
> hypervisor level on the system where the VM was running:
>
>  modprobe nf_nat_tftp
>
> And within the VM itself, run:
>
>  modprobe nf_conntrack_tftp
>

yes I have nf_conntrack_tftp loaded in the iptables-config file


>
> (You could also do modprobe nf_nat_tftp here too, because that will also
> load nf_conntrack_tftp as a dependency, but I don't think you need
> nf_nat_tftp on this end. Not harmful though, just unnecessary.)
>
> Once that was done, it connected to my laptop without an issue. This
> makes sense, because KVM is using NAT to handle networking inside VMs.
>
> I did have issues tftp'ing between two VMs on the same system, but I
> don't really think that is a very sensible setup, so I didn't pursue it
> any farther.
>
> Just for another data point, I setup a tftp server on my F14 system and
> connected from my F16 laptop as a client, and it worked fine.
>
> You might be able to get useful debugging by turning off xinetd and
> manually launching in.tftpd in a console:
>
> sudo /usr/sbin/in.tftpd -L -v -v -v -s /var/lib/tftpboot
>

Wow, TFTP works like this !

Thanks for that, now why does it not work under xinetd ?


>
> Then, in another console on the server, tail -f /var/log/messages and
> try to connect from the remote client. You might see errors like:
>
> in.tftpd[8638]: tftpd: read(ack): No route to host
>
> or
>
> in.tftpd[8613]: tftpd: read(ack): Connection refused
>
> Those usually imply a networking issue between the client and server.
> Having more information about how the client and server are networked
> together would be useful, especially if NAT is in play.
>
>
No I was not getting anything in /var/log/messages from tftpd at all only
that it was in the count of processes  started by xinetd so it was running
and connections worked.



> Hope that helps,
>

Thanks at least that is a hack I can use for now to get on !

I would like to get to the bottom of it though !

Aaron
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