Shorter ethernet cable

I'm going to go back to the original issue.  Is it truly an Ethernet cable, i.e. with RJ45 plugs?  What color is the port on the back of the Gateway is plugs into?  Red is indeed RJ45 for 1000baseT Ethernet on all four pair.  Green is RJ11 and carries VDSL2/ADSL2+ on one or two pair.

If Ethernet, just buy any Ethernet cable of the length you want.  I'm relatively sure the Gateway will take care of any MDI/MDI-X issues should they arise. 

If not Ethernet, here's some links to chose from that Amazon just offered up yesterday:

https://amazon.com/gp/product/B088T7W124/ref=pe_27541390_581310540_em_1p_5_lm

https://amazon.com/gp/product/B000083JZ0/ref=pe_27541390_581310540_em_1p_1_lm

https://amazon.com/gp/product/B07L9H97P6/ref=pe_27541390_581310540_em_1p_3_lm

What type of jack is feeding it?  Have a picture of the current cord?

Your title has the answer, you need an Ethernet cable. Being a short distance, it likely doesn’t matter whether it’s cat 5 or 6 but those seem to be most common.

While I agree the title says Ethernet, many don't know the difference between the cables, plus the asking of what kind of Ethernet cable says a lot.  If it's truly an Ethernet cable you want a straight through, not crossover.   From wall jack to the to the broadband jack on the modem could also mean a standard base cord.  So my question remains. 

Now you want to get me going on the RJ45 thing.

I guess the simplest answer then is you need the same kind of cable as the old cable with the same connectors on each end, just shorter. If you want to provide more specifics and answer the other two posters questions, they’ll identify exactly what you need.

Thanks for the quick responses.  I appreciate all of them.  The jack on the walk and on the gateway are both green and the cable itself is green.  I'm sure the connectors on the cable are RJ11's.  I'm just having a hard time finding one locally.

You will likely not find one locally.  If it's a very short run, and especially if you're not dual pair, you can try using regular old phone cable.  Without the twisted pairs, it will be subject to outside interference and (if dual pair) crosstalk.

What length are you looking for?  If you have a Best Buy or a low voltage contractor near you, you can probably have one made whatever length you want.  Don't worry much about the CAT rating as the phone cable from the Central office to your drop is CAT nothing. 

 Don't worry much about the CAT rating as the phone cable from the Central office to your drop is CAT nothing. 

Technically, yes, it doesn't fall into any EIA/TIA Categories for 4 pair cable, but the bundles still have twisted pairs in them.  And crosstalk is one of the biggest issues with DSL.