From SIPfoundry sipXecs IP PBX, The Open Source SIP PBX for Linux - Calivia

Polycom phones come factory default to use FTP with a fixed user name and password. By using FTP, you can avoid the extra step of configuring each phone to use TFTP through the cumbersome dialpad.

NOTE: With this FTP setup which uses the default polycom password, it is no more secure or insecure as TFTP.

Automatic Setup of FTP

For sipX 3.6 users on Fedora, CentOS and Redhat, you can simply run

 yum install sipxconfig-ftp

to install and configure an FTP server w/default polycom credentials.

Manual Setup of FTP

Commands to install, start ftpd and start ftpd with system on reboot:

yum install vsftpd
chkconfig vsftpd on
service vsftpd start

If you installed from RPMs...

Create new user and change password, note capitalization:

# NOTE: 3.0 and Pingtel ECS customers should SIPXUSER=sipxchange
SIPXUSER=sipx \
  adduser -d /var/sipxdata/configserver/phone/profile/tftproot \
    -G $(SIPXUSER) -s /sbin/nologin -M PlcmSpIp
echo -e "PlcmSpIp" | sudo passwd --stdin PlcmSpIp

...or if you installed from source.

 adduser -d /usr/local/sipx/var/sipxdata/configserver/phone/profile/tftproot \
    -G $(SIPXPBXUSER) -s /sbin/nologin -M PlcmSpIp
 echo -e "PlcmSpIp" | sudo passwd --stdin PlcmSpIp

 ! NOTE ! If you installed from source, /var/sipxdata/configserver/phone/profile/tftproot should be /usr/local/sipx/var/sipxdata/configserver/phone/profile/tftproot