Getting tftpd to work

[eflothmeier]

My goal is to install firmware into a Linksys router I
downloaded the firmware *.img, and would like to install
it on the target router:

Installed tftp-hpa:

and made it part of xinetd:

This is from the xinetd.conf file

.
.
.
service tftp
{
socket_type = dgram
protocol = udp
wait = yes
disable = no
user = root
server = /usr/sbin/in.tftpd
server_args = -s /tftpboot

}
.
.
.
currently it fails the self test:

erich@mmom ~/Firmware $ tftp localhost
tftp> get bkm
Transfer timed out.

No wonder. listening on port 69 is not there

mmom erich # netstat -alntp
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:21 0.0.0.0:* LISTEN 3104/xinetd
tcp 0 0 0.0.0.0:23 0.0.0.0:* LISTEN 3104/xinetd
tcp 0 0 0.0.0.0:6000 0.0.0.0:* LISTEN 2262/X
tcp6 0 0 :::6000 :::*

Checked /etc/services file and port 69 is not commented out


Looked at

https://forums.gentoo.org/viewtopic-t-1019766.html

and it looks like he got further, but I don't see how.

[Hu]

You set protocol=udp, then you listed TCP sockets. UDP sockets are not TCP sockets. What is the output of ss -nul?

[eflothmeier]

Sorry to confuse people. I meant to say
"tftp" in the subject title and not "tftpd"

[eflothmeier]

See if this is helpful:

erich@mmom ~/Firmware $ tftp -v localhost
Connected to localhost.localdomain (::1), port 69
tftp> get bkm
getting from localhost.localdomain:bkm to bkm [netascii]
Transfer timed out.

tftp>

To answer your question:

mmom ~ # ss -nul
State Recv-Q Send-Q Local Address:Port Peer Address:Port
UNCONN 0 0 *:68 *:*
UNCONN 0 0 *:69 *:*


...and with tftp running as user

mmom ~ # ss -nul
State Recv-Q Send-Q Local Address:Port Peer Address:Port
UNCONN 0 0 *:68 *:*
UNCONN 0 0 *:69 *:*
UNCONN 0 0 :::44656 :::*

[eflothmeier]

Maybe it just works:

[eflothmeier]

Many attempts have been tried. Thus far tftp has
never passed the self test.

One of the reasons tftp is non-trivial is that it is so stark.
Unlike ftp, there is no facility for showing/listing a directory once
a connection is made. Another is that there are so many recipes
for making it run. Since we installed tftp-hpa maybe a recipe
from there might work. One of the variable things is the server_args
directory.It's all over the place. Here's a sampler

/tftpboot
/home/user/tftptest
/var/lib/tftpboot
/srv/tftp

If there is a permission problem. I've never noticed error
messages to that effect.

Decided to use /var/lib/tftpboot because it has root permission
and doesn't add a new directory to the root '/'

Decided to set kernel flags:

NF_CONNTRACK_TFTP [=y]
NF_NAT_TFTP [=m]

and rebuild & install

For the first time ever, it has worked:

server:
mmom opentftp # ./opentftpd -v

client:
erich@mmom ~/tftptest $ tftp -v mmom
Connected to mmom.fgi.com (192.168.0.100), port 69
tftp> put bkm
putting bkm to mmom.fgi.com:bkm [netascii]
Sent 272 bytes in 0.0 seconds [116053 bit/s]
tftp>

Had to use mmom (the local host) using localhost still
doesn't work