(16) The prohibition of processing, including storage of communications is not intended to prohibit any automatic, intermediate and transient processing, including storage of this information insofar as this takes place for the sole purpose of carrying out the transmission in the electronic communications network. It should not prohibit the processing of electronic communications data to ensure the security, including the availability, authenticity, integrity or confidentiality, of the electronic communications services, for example checking security threats such as the presence of malware or viruses, or the identification of phishing emails. Spam e-mails may also affect the availability of email services and could potentially impact the performance of networks and e-mail services, which justifies the processing of electronic communications data to mitigate this risk. Providers of electronic communications services are encouraged to offer end-users the possibility to check e-mails deemed as spam in order to ascertain whether they were indeed spam. Neither should it prohibit the processing of metadata to ensure the necessary quality of service requirements, such as latency, jitter etc., nor the processing of metadata necessary for the purpose of management or optimisation of the network. Management or optimisation of the network refers to improving the performance and development of the network. The processing of data to make it anonymous should not be prohibited either.