From: D R (deep.ratan@gmail.com)
Date: Mon May 15 2006 - 14:46:09 ART
Mark, Thanks for your comments.
I ran some tests in on my lab routers too - sorry, new IP addressing scheme
on teh lab routers!!. Essentially, the top portion shows no change in
routing after I took off the ip route statement. The latter part of this
test shows that the routing changes once I insert the ip route statement but
goes back to what it was, once I ping the address.
thanks, Deep
R3#show run | i 255.255.255.255
ip route 10.1.3.2 255.255.255.255 10.1.3.2
R3#show ip route 10.1.3.2
Routing entry for 10.1.3.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Routing Descriptor Blocks:
* directly connected, via FastEthernet0/0
Route metric is 0, traffic share count is 1
R3#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R3(config)#no ip route 10.1.3.2 255.255.255.255 10.1.3.2
R3(config)#^Z
R3#show ip route 10.1.3.2
Routing entry for 10.1.3.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Routing Descriptor Blocks:
* directly connected, via FastEthernet0/0
Route metric is 0, traffic share count is
R3#show ip route 10.1.3.2
Routing entry for 10.1.3.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Routing Descriptor Blocks:
* directly connected, via FastEthernet0/0
Route metric is 0, traffic share count is 1
R3#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R3(config)#ip route 10.1.3.2 255.255.255.255 10.1.3.2
R3(config)#^Z
R3#show ip route 10.1.3.2
Routing entry for 10.1.3.2/32
Known via "static", distance 1, metric 0
Routing Descriptor Blocks:
* 10.1.3.2
Route metric is 0, traffic share count is 1
R3#ping 10.1.3.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.3.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
R3#show ip route 10.1.3.2
Routing entry for 10.1.3.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Routing Descriptor Blocks:
* directly connected, via FastEthernet0/0
Route metric is 0, traffic share count is 1
On 5/15/06, Mark Lasarko <mlasarko@co.ba.md.us> wrote:
>
> I understand, theoretically studying :)
> From the perspective of "Bank LAN Connection" router...
>
> I would say the second static route statement:
> ip route 170.242.246.212 255.255.255.255 170.242.246.212
>
> Will make both the .73 and .212 addresses "unroutable"
> on the "Bank_LAN_Rt"
>
> The route statements on "Bank_LAN_Router" will make it
> so the .212 (FW) device never sees a packet for these 'nets.
> (Packets originated on the "Bank_LAN_Rt")
>
> On the far side (Packets originating from the FW)
> You will not get a reply from "Bank_LAN_Rt"
> They will make it to the other side, but cannot return.
>
> So from the FW it is a one-way-dead-end;
> Packets traverse the link but do not come back
>
> On the Bank_LAN_Rt;
> Packets never make it out of the interface
>
> Once you take that second statement away:
> no ip route 170.242.246.212 255.255.255.255 170.242.246.212
>
> Then everything should flow nicely to .212, .73, etc...
>
> So my answer is:
> D) Other
>
> BTW - I misread your initial post;
> I thought you had 10.10.10.10 assigned - my bad!
> Pretty sure the above is accurate - follows routing logic.
>
> ~M
>
>
> >>> "D R" <deep.ratan@gmail.com> 05/15/06 12:00 PM >>>
>
> Yeah of course I've tried it. The router accepts the command. It's a 2600
> series router running 12.1(19).
>
> Rephrase:
>
>
> ip route 170.242.246.73 255.255.255.255 170.242.246.212*
> ip route 170.242.246.212 255.255.255.255 170.242.246.212*
>
> interface FastEthernet0/1
> description Bank LAN Connection
> ip address 170.242.246.210 255.255.255.248
> speed 100
> full-duplex
>
> 170.242.246.212 is a firewall directly connected to fa0/1.
>
> Will the command in* bold*:
>
> A) cause traffic intended for 170.242.246.73 to go into a black hole?
> B) cause traffic returning from 170.242.246.212 to go into a loop?
> C) have no effect, traffic intended for 170.242.246.73 will go out FA0/1
> as
> per normal routing process
> D) other
>
> Again, don't question the validity/purpose/legitimacy of the command. I'm
> interested to know what effect it has.
>
>
> thanks very much, DR
>
>
>
> On 5/15/06, Mark Lasarko <mlasarko@co.ba.md.us> wrote:
> >
> > ? Have you actually tried this...
> > AFAIK the router should bark at you :(
> > "%Invalid next hop address" or similar message.
> > ~M
> >
> >
> > >>> "D R" <deep.ratan@gmail.com> 05/15/06 8:38 AM >>>
> > Gents, Rudimentary question:
> >
> > FA0/1 is configured with 10.10.10.1 255.255.255.0 and is up/up.
> >
> > in global config mode:
> >
> > ip route 10.10.10.10 255.255.255.255 10.10.10.10
> >
> > The static route config above will:
> >
> > A) cause a routing loop
> > B) have no effect
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Thu Jun 01 2006 - 06:33:21 ART