I believe IXP networks are usually like this. Globally assigned IPs, and routers can use their IPs on the network to originate ICMP packets (e.g. TTL exceeded during traceroute; or packet too big) but putting a route to the IXP network on the internet is strictly prohibited.
On 19 August 2025 20:40:20 CEST, "Jakob Heitz (jheitz) via NANOG" <[email protected]> wrote: >ICMP packets from internal devices. Example “unreachable”. > >Kind Regards, >Jakob > > >---------------------------- >Question: Can a prefix be never routed on the Internet but used only one-way >for source address in IP packets? > >That is. a user owns an IP prefix. They never advertise a route to it in BGP >on the Internet. But they use the prefix solely for source address in IP >traffic from a source to a destination (sink). In this set up, the >destination server obviously cannot/doesn't return any acknowledgements etc. >to the source. Anyone aware if there is any such known application in use on >the Internet - even if it is rare? Thanks. > >Sriram > > >_______________________________________________ >NANOG mailing list >https://lists.nanog.org/archives/list/[email protected]/message/HXWFW2SZEFHND7TZNN2MWA6E4V3QLZ3E/ _______________________________________________ NANOG mailing list https://lists.nanog.org/archives/list/[email protected]/message/3HEKBQOKOK2EXFDQSWWY5UTVE3LI4YU5/
