Sì, a patto di essere un po’ scafati e di avere una macchina in rete su cui installare servizi IP over DNS o IP over ICMP. Make spiega i dettagli:

In most situations, the firewall will be set up to block or proxy all TCP traffic, and all HTTP requests are redirected to the authentication server that wants you to enter a credit card. DNS lookups and ICMP traffic (ping, for example) are quite often left untouched, however, allowing you to use these services to move data through a remote computer under your control.