Protocol spoofing

Protocol spoofing is used in data communications to improve performance in situations where an existing protocol is inadequate, for example due to long delays or high error rates.

Note: In a computer security context, spoofing refers to various forms of falsification of data. The spoofing techniques discussed here are legitimately used to improve performance, not to attack systems.

Spoofing techniques

In most applications of protocol spoofing, a communications device such as a modem or router simulates ("spoofs") the remote endpoint of a connection to a locally attached host, while using a more appropriate protocol to communicate with a compatible remote device that performs the equivalent spoof at the other end of the communications link.

UUCP spoofing

The UUCP "g" protocol performs badly when used over links with highly asymmetric transfer speeds. Modems like Trailblazer or Multitech products simulate the remote endpoint to the local host in order to avoid slow high/low speed direction changeovers.

TCP spoofing

TCP connections may suffer from performance limitations due to insufficient window size for links with high bandwidth x delay product, and on long-delay links such as those over GEO satellites, TCP's slow-start algorithm significantly delays connection startup. A spoofing router terminates the TCP connection locally and uses protocols tailored to long delays over the satellite link.

RIP/SAP spoofing

SAP and RIP periodically broadcast network information even if routing/service tables are unchanged. dial-on-demand WAN links in IPX networks therefore never become idle and won't disconnect. A spoofing router or modem will intercept the SAP and RIP broadcasts, and re-broadcast the advertisements from its own routing/service table that it only updates when the link is active for other reasons.

See also

• TCP Westwood
• TCP tuning

External links

• UUCP `g' Protocol
• http://gltrs.grc.nasa.gov/reports/2001/TM-2001-211151.pdf. {{cite journal}}: Cite journal requires |journal= (help); Missing or empty |title= (help); Unknown parameter |Author= ignored (|author= suggested) (help); Unknown parameter |PublishYear= ignored (help); Unknown parameter |Title= ignored (|title= suggested) (help)