79 lines
2.7 KiB
Markdown
79 lines
2.7 KiB
Markdown
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---
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date: 2013-03-25
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title: Writeable TFTP Server On CentOS
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category: linux
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---
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Well this caught me out for an embarassingly long time. There are
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[loads](https://blog.penumbra.be/tag/tftp/)
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[of](https://www.question-defense.com/2008/11/13/linux-setup-tftp-server-on-centos)
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[examples](https://wiki.centos.org/EdHeron/PXESetup) of setting up a
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TFTP server on the web. The vast majority of them assume that you are
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using them read-only for PXE booting.
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I needed to make it writeable so that it could be used for storing
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switch/router backups. It is trivially simple once you have read the man
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page (pro tip: RTFM).
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I am doing this on RHEL6, it should be fine on Centos, Scientific Linux
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or Fedora as is. Any other distro it will require some modification.
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First install it (install the client as well to test at the end:
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yum install tftp tftp-server xinetd
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chkconfig xinetd on
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Now edit the file \`/etc/xinetd.d/tftp to read:
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service tftp
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{
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socket_type = dgram
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protocol = udp
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wait = yes
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user = root
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server = /usr/sbin/in.tftpd
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server_args = -c -s /var/lib/tftpboot
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disable = no
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per_source = 11
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cps = 100 2
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flags = IPv4
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}
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There are 2 changes to this file from the defaults. The `disable` line
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enables the service. Normally that is where you leave it. However, you
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cannot upload to the server in this case without pre-creating the files.
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The second change adds a `-c` flag to the `server_args` line. This tells
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the service to create the files as necessary.
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It still will not work though. You need to tweak the filesystem
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permissions and SELinux:
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chmod 777 /var/lib/tftpboot
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setsebool -P tftp_anon_write 1
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Of course you'll also need to open up the firewall. So add the
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following line to `/etc/sysconfig/iptables`:
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-A INPUT -m state --state NEW -m udp -p udp -m udp --dport 69 -j ACCEPT
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If your IPtables set up is what comes out of the box, there will be a
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similar line to allow SSH access (tcp:22), I would add this line just
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after that one. If you have something more complicated, then you will
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probably know how to add this one as well anyway.
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You should now be able to upload something to the server
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echo "stuff" > test
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tftp localhost -c put test
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Your test file should now be in `var/lib/tftpboot`.
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One final note with regards to VMware. This does not work if you are
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using the VMXNET3 adapter, so make sure you are using the E1000. GETs
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will work and the file will be created, but no data will be put on the
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server. To annoy you even more, the test PUTting to localhost will work,
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but PUTs from a remote host will not.
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It has been noted in the VMware forums
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[here](https://communities.vmware.com/thread/215456)
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