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How to disable TFTP on VDX6720

How to disable TFTP on VDX6720

Adam_Schappell
New Contributor
Hello, we have a requirement to have TFTP disabled on our switch... Is this possible? If so what commands can I run?
1 ACCEPTED SOLUTION

Truyen_Phan
Extreme Employee
Hi Adam,

TFTP is executed under the inetd process. TFTPd is disabled by default on higher releases (6.x+) which the 6720 does not support. IPfilter is not needed to block this.

Please do the following to disable tftpd. A reload will be needed to take effect.

The below will do the following:

  1. take back up of inetd.conf
  2. comment out tftpd in inetd.conf and put in new file via sed
  3. overwrite inetd.conf with update file
  4. copy inetd.conf to 2nd partition in case of partition swap in the future
  5. reload switch
code:
sw0# unhide foscmd
Password: ******** (fibranne)
sw0# fos bash | no
sw0:root> netstat -anp | grep :69
udp 0 0 0.0.0.0:69 0.0.0.0:* 1295/inetd

sw0:root> cat /etc/inetd.conf | grep tftpd
tftp dgram udp wait nobody /usr/sbin/in.tftpd in.tftpd /tftpboot

bash-2.04# cp /etc/inetd.conf /etc/inetd.conf.bak
bash-2.04# cp /mnt/etc/inetd.conf /mnt/etc/inetd.conf.bak
bash-2.04# sed -e 's/^tftp/#tftp/' /etc/inetd.conf > /etc/inetd.conf.new
bash-2.04# cp /etc/inetd.conf.new /etc/inetd.conf
bash-2.04# grep tftp /etc/inetd.conf
#tftp dgram udp wait nobody /usr/sbin/in.tftpd in.tftpd /tftpboot

bash-2.04# cp /etc/inetd.conf /mnt/etc/inetd.conf
bash-2.04# exit
exit
sw0# reload system


### After switch boots up ###

code:
sw0# unhide foscmd
Password: ******** (fibranne)
sw0# fos bash | no
bash-2.04# netstat -anp | grep :69
bash-2.04#

View solution in original post

25 REPLIES 25

Adam_Schappell
New Contributor
Any way to disable that on 4.1.3?

Ivan_Chan
Extreme Employee
yeah. TFTP is using well known port 69 UDP

69 UDP TFTP (Trivial File Transfer Protocol) Offical

Ivan_Chan
Extreme Employee
on 4.1.3 it does not have vrf context - which is added in NOS 5.0

Adam_Schappell
New Contributor
Looks like port 69/UDP

Ivan_Chan
Extreme Employee
check sh proc cpu and not seeing tftpd running, that it can be disabled ...
GTM-P2G8KFN