From: D R (deep.ratan@gmail.com)
Date: Thu May 18 2006 - 11:31:32 ART
Jim, Thanks for your feedback and input but we're off on the ip addresses
for this test. In my question, the ip route statement is not for the same
address that is configured on one of my router interfaces, as you have in
your test.
I have (example):
FA0/1 = 10.10.10.1 /24
ip route 10.10.10.101 255.255.255.255 10.10.10.200
ip route 10.10.10.200 255.255.255.255 10.10.10.200
10.10.10.200 <http://170.242.246.212/> is a firewall directly connected (via
a switch) to fa0/1.
Will the 2nd ip route statement** (ip route 10.10.10.200 255.255.255.255
10.10.10.200):
A) cause traffic intended for 10.10.10.101 <http://170.242.246.73/> to go
into a black hole?
B) cause traffic returning from 10.10.10.200 <http://170.242.246.212/> to go
into a loop?
C) have no effect, traffic intended for
10.10.10.101<http://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. I ran this test and a somebody at
Cisco ran the same test. We get different results. Maybe an IOS issue...
On 5/15/06, firstname jim <firstnamejim@gmail.com> wrote:
>
> I tried this on the lab, there is isn't any effect. There is no effect
> even when I set the destination out to a different interface:
>
> int fa 0/0
> ip address 10.0.0.1 255.255.255.0
> no shut
> int fa 0/1
> ip address 20.0.0.1 255.255.255.252
> no shut
> ip route 10.0.0.1 255.255.255.255 20.0.0.2
>
> r1#show ip ro
> 20.0.0.0/30 is subnetted, 1 subnets
> C 20.0.0.0 is directly connected, FastEthernet0/1
> 10.0.0.0/24 is subnetted, 1 subnets
> C 10.0.0.0 is directly connected, FastEthernet0/0
>
>
> I think we have to understand it at both routing table and layer 2 arp
> levels.
> The router seems to know its own interface IP address, and will ignore the
> static
> host route. Also, it certainly has that
> permanently in its arp table. I did span on both ports, and never saw any
> packet
> being sent out or received. So all that icmp echo/reply was handled
> internally.
> It ignored the static host route (in fact, it didn't show up in the
> routing table). R1
> knows it has 10.0.0.1 out interface fastethernet 0/0.
>
>
> Here is the output of a ping packet (with debug ip packet detail)
> r1#ping 10.0.0.1 repeat 1
>
> Type escape sequence to abort.
> Sending 1, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds:
> !
> Success rate is 100 percent (1/1), round-trip min/avg/max = 8/8/8 ms
> r1#
> *Mar 1 20:00:12.215: IP: tableid=0, s=10.0.0.1 (local),
d=10.0.0.1(FastEthernet0/0), routed via RIB
> *Mar 1 20:00:12.215: IP: s= 10.0.0.1 (local), d=10.0.0.1(FastEthernet0/0),
len 100, sending
> *Mar 1 20:00:12.215: ICMP type=8, code=0
> *Mar 1 20:00:12.215: IP: tableid=0, s=10.0.0.1 (FastEthernet0/0), d=
> 10.0.0.1 (FastEthernet0/0), routed via RIB
> *Mar 1 20:00:12.215: IP: s=10.0.0.1 (FastEthernet0/0), d=10.0.0.1
(FastEthernet0/0),
> len 100, rcvd 3
> *Mar 1 20:00:12.219: ICMP type=8, code=0
> *Mar 1 20:00:12.219: IP: tableid=0, s=10.0.0.1 (local),
d=10.0.0.1(FastEthernet0/0), routed via RIB
> *Mar 1 20:00:12.219: IP: s=10.0.0.1 (local), d=10.0.0.1(FastEthernet0/0),
len 100, sending
> *Mar 1 20:00:12.219: ICMP type=0, code=0
> *Mar 1 20:00: 12.219: IP: tableid=0, s=10.0.0.1 (FastEthernet0/0), d=
> 10.0.0.1 (FastEthernet0/0), routed via RIB
> *Mar 1 20:00:12.219: IP: s=10.0.0.1 (FastEthernet0/0),
d=10.0.0.1(FastEthernet0/0), len 100, rcvd 3
> *Mar 1 20:00:12.223: ICMP type=0, code=0
>
> And just to make sure my span and remote span worked,
> I did other pings and received ARP requests:
> 22:51:00.625509 IP (tos 0x0, ttl 255, id 81, offset 0, flags [none], proto
> 1, length: 100) 10.0.0.1 > 10.0.0.10: icmp 80: echo request seq 0
> 22:51:00.625538 IP (tos 0x0, ttl 255, id 81, offset 0, flags [none], proto
> 1, length: 100) 10.0.0.1 > 10.0.0.10: icmp 80: echo request seq 0
> 22:51:46.445679 arp who-has 20.0.0.2 tell 20.0.0.1
> 22:51:46.445727 arp who-has 20.0.0.2 tell 20.0.0.1
>
>
>
>
>
> On 5/15/06, D R <deep.ratan@gmail.com> wrote:
> >
> > All, I am not asking about the validity/usefulness of configuring the
> > static
> > route below. I just want to confirm if doing so will have no effect
> > (packets
> > for 10.10.10.10 will get routed out to FA0/1 as per normal routing
> > process,
> > or if the static route will cause any problems.
> >
> > thanks, DR
> >
> > On 5/15/06, D R <deep.ratan@gmail.com> wrote:
> > >
> > > 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
> >
>
>
>
> --
> Jim Li
> 614-376-2865
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