all 5 comments

[–]madmike78CCNA RS - CCNA SEC in progress 2 points3 points  (1 child)

do you have the same ISP as work?

I would not be surprised if they forgot to block RFC 1918 space at either the customer edge or the provider edge.

I have seen other anomolies. Once someone plugged a hub up outside our router and used it to connect to the ISP and also our main switch stack. We got a call from a local garage way out in Alabama (same town as our remote site) saying a welcome message popped up. Turns out the hub was allowing the DHCP traffic to go upstream and he was working off of our network connection.

[–]pdub103[S] 2 points3 points  (0 children)

Same ISP. Hearing you say it, I bet they just aren't blocking it at the edge, and these are their hosts (servers, management, etc...).

[–]Propulsions🍁🛢️🌩️!!!! 2 points3 points  (2 children)

A traceroute takes me through my gateway then a couple of 100.127.x.x hosts,

That's cool, you're ISP should be filtering private addresses but you're going through their network.

Who's your ISP?

[–]pdub103[S] 0 points1 point  (1 child)

Right? I wonder how long it'll go before someone sees it. Cox is my ISP.

[–]_chrisjhartCCNA R&S 2 points3 points  (0 children)

Ahh! Cox is the only ISP that I know of that definitely does this, although I'm certain that there are a few others that do as well.

This is actually documented fairly well on the internet! It's definitely a Cox thing.

The 100.127.x.x hosts are actually part of CGN (Carrier-Grade NAT), as that falls within the reserved range for CGN ( –