?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Bad+Packets+Come+Back%2C+Worse+Ones+Don't&rft.creator=Gigis%2C+Petros&rft.creator=Handley%2C+Mark+James&rft.creator=Vissicchio%2C+Stefano&rft.description=ISPs+may+notice+that+traffic+from+certain+sources+is+entering+their+network+at+an+unexpected+location%2C+but+it+is+hard+to+know+if+this+represents+a+problem+or+is+just+normal+spoofed+background+noise.+If+such+traffic+is+not+spoofed%2C+it+would+be+useful+to+generate+alerts%2C+but+alerting+on+background+noise+is+not+useful.%0D%0AWe+describe+Penny%2C+a+test+ISPs+can+run+to+tell+unspoofed+traffic+aggregates+arriving+on+the+wrong+port+from+spoofed+ones.+The+idea+is+simple%3A+when+receiving+new+traffic+at+unexpected+routers%2C+drop+a+few+TCP+packets.+Non-spoofed+TCP+packets+(%22bad+packets%22)+will+be+retransmitted+while+spoofed+ones+(%22worse+packets%22)+will+not.+However%2C+building+a+robust+test+on+top+of+this+simple+idea+is+subtle.+We+show+how+to+deal+with+conflicting+goals%3A+minimizing+performance+degradation+for+legitimate+flows%2C+dealing+with+external+conditions+such+as+path+changes+and+remote+packet+loss%2C+and+ensuring+robustness+against+spoofers+trying+to+evade+our+test.&rft.subject=traffic+testing%2C%0D%0AISPs%2C%0D%0Ainternet+routing%2C%0D%0AIP+spoofing%2C%2C%0D%0ATCP%2C%0D%0ABGP&rft.publisher=Association+for+Computing+Machinery+(ACM)&rft.date=2024&rft.type=Proceedings+paper&rft.language=eng&rft.source=+++++In%3A++ACM+SIGCOMM+'24%3A+Proceedings+of+the+ACM+SIGCOMM+2024+Conference.++(pp.+pp.+311-326).++Association+for+Computing+Machinery+(ACM)%3A+Sydney%2C+NSW%2C+Australia.+(2024)+++++&rft.format=text&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F10195697%2F1%2FPenny_sigcomm24.pdf&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F10195697%2F&rft.rights=open