Seguinte pessoal, seguindo as idéias que me forneceram eu apaguei o arquivo known hosts das duas máquinas e tentei realizar a cópia novamente, mais a mensagem continua a mesma.
Quero realizar esta cópia via script na parte da madrugada, então por isso gostaria de realizá-la via linha de comando.
root@master:~# scp
root@172.16.0.15:~/iptables root@172.16.0.6:~/The authenticity of host '172.16.0.15 (172.16.0.15)' can't be established.
RSA key fingerprint is 57:4b:47:9c:4a:2b:ed:22:08:60:51:3b:0d:47:75:c4.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '172.16.0.15' (RSA) to the list of known hosts.
root@172.16.0.15's password:
Host key verification failed.
lost connection
xfree: NULL pointer given as argument
root@master:~#