SBS 2003: Configuring ISA 2004 behind a Router for Router to Router VPN Tunnel. - Blog of the EMEA SBS Team - Site Home - TechNet Blogs Sign In Blog of the EMEA SBS Team SBS 2003: Configuring ISA 2004 behind a Router for Router to Router VPN Tunnel. TechNet Blogs > Blog of the EMEA SBS Team > SBS 2003: Configuring ISA 2004 behind a Router for Router to Router VPN Tunnel.