Re: Issue with some unnamed ISP's in northern north america, RFC 1918 Violation
Laszlo H via NANOG <[email protected]>
| Newsgroups | gmane.org.operators.nanog |
|---|---|
| Message-ID | <[email protected]> |
Not sure if you meant Comcast but it sounds similar to what they do. I think they are using RIP not BGP, but it works the way you're describing. You have to statically configure the static IP and gateway - if you let it DHCP it will get one of those 10.x.x.x numbers. It's just two addresses on the same interface on the CPE: the 10.x.x.1 IP and also the first address from your static IP block. On 3/10/26 9:13 PM, wolf1098--- via NANOG wrote: > One of the fibre providers, they are issuing static ips, which is good, but the way the statics are handled. The modem/router, if you want static ips, requires it to be in router mode, you can't bridge. it seems the router's static ip gateway does some bgp towards the isp to route the static ip's block assigned to the customer to it, via its dhcp established route??? idk. ------ THE big issue, which is, since it has to be in router mode. they end up with a dynamic ip, that is the gateway for dhcp RFC1918 addresses, that are on its lan, sounds reasonable, but as a tertiary use, the static ip WAN gw stack, LOADS IN ON the same L2 lan bridge, side by side with the RFC 1918 space, without even attempting to put it in a tagged vlan. don't do this.... without using a custom linux router, good luck using both the static ips block, and the double 'natted' dynamic ip. > _______________________________________________ > NANOG mailing list > https://lists.nanog.org/archives/list/[email protected]/message/CWEOU5LH5DZ4OISZZ6DC4OZELSZXNZN4/ _______________________________________________ NANOG mailing list https://lists.nanog.org/archives/list/[email protected]/message/TRJNIFSSBQGTUWFCGZZVDDJ654RL4Y6T/