For JUNOS I think that you are looking for user@lab> show forwarding-options load-balance ? Possible completions: destination-address Destination IP address destination-port Destination port family Layer 3 family ingress-interface Ingress Logical Interface packet-dump Raw packet dump in hex without '0x' source-address Source IP address source-port Source port tos Type of Service field transport-protocol Transport layer protocol
Nitzan On Tue, Aug 12, 2025 at 5:58 PM Saku Ytti via NANOG <[email protected]> wrote: > Hey-o, > > > Which platform/software has a command to show which interface will be > used for forwarding with given keys? > > ASR9k has a cef exec-route, and I see references to this in c-nsp, > reddit and cisco.com forums, stressing how useful debugging tool it > has been. Despite it not actually working, since it's just RE > software, it doesn't talk to the EZchip/lightspeed, unless it has been > fixed in the past couple of years, certainly hasn't worked in the > timeline of various forums finding it useful. > > MX has 'jsim' > https://www.juniper.net/documentation/en_US/day-one-books/TW_MX3D_PacketWalkthrough.pdf > which I think actually works, but it is quite involved. I have some > (false?) memory that I saw in some release note this being a bit more > productised into CLI command, but I'm failing to find anything to > support this memory. > > There is also RFC5837, which is actually implemented in QFX5k, but not > for TTL exceeded, we've opened ER to get it supported on MX and PTX > and for TTL exceeded. This RFC will allow programmatic platform > agnostic discovery of the actual interface used, without relying on > platform specific magic. So please do ask your vendors to implement > it. > > -- > ++ytti > _______________________________________________ > NANOG mailing list > > https://lists.nanog.org/archives/list/[email protected]/message/65IZUIUM3WTM56W3CLM6HOGK2T7DCEKF/ > _______________________________________________ NANOG mailing list https://lists.nanog.org/archives/list/[email protected]/message/HHWSKHAH2RWUUZN5XMLUCOKMCCLXCK77/
