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Like if host address is 100.0.0.1 and next hop address is 100.0.0.2 and destination ip address is also 100.0.0.2
Is this a valid use case? Any real life usage?
<dest ip> <next hop>
ip route 100.0.0.2 255.255.255.255 100.0.0.2 weight 1 next-hop-vrf GlobalRouter
Above is the command on a router inside a VRF. 100.0.0.2 is pingable from host. 100.0.0.1 & 100.0.0.2 are an ip address assigned to a VLAN on host & destination respectively.
On a linux box, Such configuration is valid.
[root]# netstat -r -n
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
55.55.55.55 55.55.55.55 255.255.255.255 UGH 0 0 0 eth0
[root]# ip route show
55.55.55.55 via 55.55.55.55 dev eth0
As per my understanding, If a destination IP is reachable (i.e in the same subnet of host IP) we dont need a next hop.
I came across one application for using next hop for destination IP in same subnet (i.e for VPN) See this: Will packets send to the same subnet go through routers?
If next hop != destination IP but they are in same subnet as that of host, is a valid scenario for VPN, then i am wondering what are the applications of next_hop==dest_ip & subnet same as host?
This is my first post in Super User. Extremely happy with the quick and warm response.
How on earth has this got 4 close votes? – barlop – 2014-05-28T12:43:12.310
I notice in my routing table, win7 on a comp with IP of 10.0.0.2 there is a line that says- 10.0.0.2 255.255.255.255 On-link 10.0.0.2 276 I am a bit rusty though. – barlop – 2014-05-28T12:44:39.960
Somebody asked about ARP and that was considered OK. Why not this question? – barlop – 2014-05-28T12:45:23.833
raj, in that last line, is that meant to be a command or is that meant to be output? i either way, better to provide a screenshot so we can see OS and column headings and what it looks like really – barlop – 2014-05-28T14:32:45.230
I just fixed up the formatting. For some reason superuser messes up the formatting of things by default and the thing to do is to highlight some parts where formatting matters and to click the button called "code sample". – barlop – 2014-05-28T21:25:29.240
What is 55.55.55.55? It doesn't look like it'd be an internal ip address (unless you saw an internal address and changed it to that in your post perhaps so people wouldn't no your internal ip though there's no risk there) Or is it to represent an external ip? – barlop – 2014-05-28T21:30:40.293
It is a dummy internal IP addr assigned to eth0:1 of peer node. And hence pingable – Raj – 2014-05-29T05:08:20.453
I've seen TCP/IP networking questions accepted before. You could try serverfault though they s prefer practical questions from administrators. Often people don't understand questions that aren't practical.. moreso here. And TCP/IP is over the heads of a lot pf people. You could try the arstechnica forum, networking section. You will go over the heads of some people there too but they are not as rigid – barlop – 2014-05-29T17:25:12.257