[c-nsp] HSRP, and the router on the other side...

[Rick Coloccia]

Hi Everyone,

Please view this message in a fixed width font for the bad ascii art to 
make sense... thanks!

I have an HSRP question, I'm hoping someone here can clarify something 
for me that isn't made clear in any of the many "how to use HSRP" web 
sites all over the web.

Most of HSRP makes sense to me:

plug many hosts into a switch
plug the switch into 2 routers
configure the two interfaces on the routers to belong to the same hsrp 
group and to share a third virtual ip address
tell the many hosts that the virtual ip address is their router.

on the two routers, tell each that their upstream router is exactly who 
it is.  In my case I am using a static route from each of the two 
routers to a third router that is upstream from both of these two 
routers doing the hsrp.

Here's my question:  How do I tell the upstream router to get back to my 
hosts via the switch on which the virtual ip address resides?



             +---+    +---+      +------+
             | s |----| R |------|      |
+-------+    | w |    | 1 |      |      |
| host1 |----| i |    +---+      |      |   +-------+
+-------+    | t |               | core |---| host2 |
             | c |    +---+      |      |   +-------+
             | h |----| R |------|      |
             +---+    | 2 |      |      |
                      +---+      +------+


addresses:
host1: 10.10.10.10/24
r1, int connected to switch: 10.10.10.2/24
r2, int connected to switch: 10.10.10.3/24
virtual address shared by r1 and r2: 10.10.10.1/24

r1 and r2 connect to the core, both in vlan 7.

r1, int connected to the core: 10.10.11.2/24
r2, int connected to the core: 10.10.11.3/24
int vlan 7 in the core: 10.10.11.1/24

host2 is in vlan8 in the core: 10.10.12.10/24
int vlan8 in the core: 10.10.12.1/24


so my question, restated, is this:

What is the route that I should have in the core for it to know how to 
get traffic to hosts in the 10.10.10.0/24 net?

ip route 10.10.10.0 255.255.255.0 10.10.10.2
and/or
ip route 10.10.10.0 255.255.255.0 10.10.10.3
and/or
ip route 10.10.10.0 255.255.255.0 Vlan7

A related question:
I am getting dropped traceroute packets when I try to traceroute to one 
of the three addresses involved in the HSRP, but never a packed is 
dropped when connecting to a host behind the hsrp routers.  Is that 
normal? 

traceroute to 10.10.10.3(10.10.10.3), 30 hops max, 38 byte packets
 1  10.10.12.1  0.284 ms  0.207 ms  0.202 ms  0.196 ms
 2  10.10.11.2  0.446 ms  0.430 ms  0.44
 3  10.10.10.3  0.507 ms *  0.545 ms *

See the *  instead of the times?  I don't know what that's all about.  
Can someone enlighten me?

I know there's a lot here, thanks very much in advance for looking this 
over!  Maybe the replies will be helpful for others...

Thanks,

-Rick



-- 
Rick Coloccia, Jr.
Network Manager
State University of NY College at Geneseo
1 College Circle, 119 South Hall
Geneseo, NY 14454
V: 585-245-5577
F: 585-245-5579

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