Solved Unable to connection TFTP.

[Richard Nihells]

I am having an issue getting Fog setup. I can’t connect to the TFTP server. I have gone through the troubleshooting steps on the Fog project website the best I could. Can’t find the config.php file.

I am running fog on a CentOS VM and I set it up a couple of weeks ago. This was a clean install of Fog and CentOS.

When trying to test on Windows, I get this.
Error on server : Permission denied
Connect request failed.

When trying to have a blank VM do a PXE boot over the network I get this.
PXE-T00: Permission denied
PXE-E36: Error received from TFTP server
PXE-M0F: Exiting Intel PXE ROM.

Not sure if I missed any details that are needed to help with this. If you need more information I will be happy to provide.

[cevanwells]

If you don’t want to disable selinux (or set to permissive) I’ve had luck under CentOS 7 using the following command:

$ sudo setsebool -P tftp_home_dir 1

I thought I might expound a little. To test my Fog TFTP server, I used the TFTP client in Windows. If you would like to do the same, you need to permit TFTP through your Windows firewall.

When I first tried to pull the undionly.kpxe file using the Windows client, I was given the following error:

PS C:\Users\jarcher> tftp -i 172.19.1.30 GET undionly.kpxe
 Connect request failed

Looking into my /var/log/audit/audit.log file I saw the following:

$ sudo grep tftp /var/log/audit/audit.log
...lots of other stuff here...
type=AVC msg=audit(1519225691.090:214): avc:  denied  { read } for  pid=3164 comm="in.tftpd" name="undionly.kpxe" dev="dm-0" ino=34386610 scontext=system_u:system_r:tftpd_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:default_t:s0 tclass=file
...also lots more here...

if you use audit2allow you can get some hints on how to fix this error:

$ sudo grep tftp /var/log/audit/audit.log | audit2allow -m tftpd

module tftpd 1.0;

require {
        type default_t;
        type tftpd_t;
        class file { getattr lock open read };
}

#============= tftpd_t ==============

#!!!! WARNING: 'default_t' is a base type.
#!!!! This avc can be allowed using the boolean 'tftp_home_dir'
allow tftpd_t default_t:file { getattr lock open read };

Note, you might have to install the policycoreutils-python package to get audit2allow

Now just run the original command I mentioned above to allow access to the files:

$ sudo setsebool -P tftp_home_dir 1

SELinux is still set to enforcing:

$ sestatus
SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
SELinux root directory:         /etc/selinux
Loaded policy name:             targeted
Current mode:                   enforcing
Mode from config file:          enforcing
Policy MLS status:              enabled
Policy deny_unknown status:     allowed
Max kernel policy version:      28

And now the TFTP transfer works in Windows:

PS C:\Users\jarcher> tftp -i 172.19.1.30 GET undionly.kpxe
Transfer successful: 95338 bytes in 1 second(s), 95338 bytes/s

[Sebastian Roth]

@Richard-Nihells Any news on this?

[Richard Nihells]

Thank you for the links! I will look over this material and get back with you once I have an update. Going to do the re-install as well as suggested.

[george1421]

Also Wayne put together a pretty detailed install guide here: https://wiki.fogproject.org/wiki/index.php?title=CentOS_7

[Wayne Workman]

@richard-nihells said in Unable to connection TFTP.:

Is that in the Fog documentation somewhere or just somewhere on Google?

Our documentation is community driven, and is mostly here: https://wiki.fogproject.org/wiki/index.php?title=Main_Page

[Wayne Workman]

@richard-nihells now that selinux is disabled, re-run the installer and try again. Also ensure you’ve setup firewalld correctly? That’s in the troubleshooting guide too (as well as our CentOS 7 tutorial).

[Richard Nihells]

I set selinux to permissive. I no longer get permission denied. Now I get connection timeout. I have my anti-virus suite and Windows Firewall disabled during this test.

[Richard Nihells]

I found that line in the troubleshooting guide and that is what is giving me the error for Windows that I listed above.

I haven’t touched selinux or changed its settings to permissive. Is that in the Fog documentation somewhere or just somewhere on Google?

[george1421]

Did you disable selinux or at least change the settings to permissive?

From a windows computer install the tftp client feature, then from a windows command prompt use the tftp client program to download undionly.kpxe from the fog server with tftp -i <fog_server_ip> GET undionly.kpxe . If you can get the file then tftp is setup correctly and we need to focus on the pxe booting process at the cause.