While that is still a serious risk, IP packets support a source routing header option header.<p><a href="http:&#x2F;&#x2F;www.networksorcery.com&#x2F;enp&#x2F;protocol&#x2F;ip&#x2F;option003.htm" rel="nofollow">http:&#x2F;&#x2F;www.networksorcery.com&#x2F;enp&#x2F;protocol&#x2F;ip&#x2F;option003.htm</a><p><a href="http:&#x2F;&#x2F;www.networksorcery.com&#x2F;enp&#x2F;protocol&#x2F;ip&#x2F;option009.htm" rel="nofollow">http:&#x2F;&#x2F;www.networksorcery.com&#x2F;enp&#x2F;protocol&#x2F;ip&#x2F;option009.htm</a><p>I have no idea how well supported these headers are on the modern internet, but they are still part of the protocol.