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