08-14-2012 04:54 PM
Hello,
I have not used any IOS product before this week.
Can someone verify there is nothing missing from this config for the Ethernet0 interface to work properly?
I have read many posts about interface issues on the network that require attention to network interface configs on the switch side (disabling auto-negotiation, fixed 10Mbps, half-duplex).
I am trying to assign 10.40.20.51 to interface Ethernet0
My gateway is 10.40.23.254
Thank you!
Art.
-------------
LA-AS#show startup-config
Using 816 out of 32762 bytes
!
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname LA-AS
!
logging rate-limit console 10 except errors
enable secret 5 $1$oH4m$afnnZjU0EF92dCJ.VVPq61
!
username admin password 0 admin1
ip subnet-zero
no ip finger
no ip domain-lookup
!
!
!
!
interface Ethernet0
ip address 10.40.20.51 255.255.252.0
!
interface Serial0
no ip address
shutdown
no fair-queue
!
ip default-gateway 10.40.23.254
ip classless
ip route 0.0.0.0 0.0.0.0 10.40.23.254
no ip http server
!
!
line con 0
logging synchronous
login local
transport input none
line 1 16
no exec
exec-timeout 0 0
no flush-at-activation
transport input all
line aux 0
logging synchronous
login local
line vty 0 4
logging synchronous
login local
!
end
Solved! Go to Solution.
09-05-2012 03:45 PM
Art
This output is quite surprising. The good news is that the arp output does demonstrate that at layer 2 you are communicating (and I believe this demonstrates that your transceiver is not faulty). The surprising thing is that at layer 3 there seems to be a problem.
One thing that might help would be if you post the output of show cdp neighbor detail. This is another way of demonstrating that the interface is communicating.
One thought that occurs to me is that some devices have firewalls (or in the case of routers may have access lists) that do not allow response to ping. So one question would be whether other devices on this network can ping to 10.40.23.254 or to 10.40.20.250. Another question would be whether these devices can ping to your 2511.?
And just a comment - you have been giving us output of show startup-config. It would be slightly better if it were the output of show running-config. Most of the time the two outputs would be the same. But in the instances where they are different it is the running-config that is what the router is actually doing.
HTH
Rick
08-14-2012 07:15 PM
I noticed that when I tried to isolate the access server behind a router on a simple Class C network (netmask 255.255.255.0), I noticed the ip route commands were accumulating data into a routing table as opposed to replacing the last entry. So, do I need both of these directives?
ip default-gateway 10.40.23.254
ip route 0.0.0.0 0.0.0.0 10.40.23.254
How can I get rid of the ip route line? I will RTFM that...
08-22-2012 10:13 PM
Art
I do not understand your comment about accumulating entries when you put the 2511 behind a router with /24 mask. Perhaps you can clarify? Also can you tell us when you put it behind a /24 mask did you leave the /22 mask on the 2511 or did you change it?
When ip routing is enabled (and it is enabled by default on Cisco routers) then you do not need ip default-gateway. This command is only used if ip routing is disabled and the router is acting as an IP host. It does not hurt to have it in the config, but in normal operation it is not used. The router needs the ip route statement to configure static routes or it needs to run a dynamic routing protocol.
HTH
Rick
Sent from Cisco Technical Support iPad App
08-28-2012 06:50 PM
Hello,
Thank you for taking an interest in assisting...
For starters.... now I see how to remove a config line (just prepend 'no' to the same line)
By accumulating, I was merely referring to how the route entries accumulate and must be removed with the prepended 'no' directive.
And Yes to changing the netmask to a Class C (255.255.255.0) before testing. That was just a curiosity test connecting it to an old style BEFRS41. Remember those? I am back to trying to get a ping sent out on the 10.40.20.0/22 network.
After looking at this again and again... it seems that I have a routing issue. Perhaps the area you speak of is where I need to set some directives. With a no directive, I can remove the two existing route entries:
ip default-gateway 10.40.23.254
ip route 0.0.0.0 0.0.0.0 10.40.23.254
How do I get this ip routing thing happening?
Many thanks!
And you probably want this report, I'd imagine:
#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is 10.40.23.254 to network 0.0.0.0
10.0.0.0/22 is subnetted, 1 subnets
C 10.40.20.0 is directly connected, Ethernet0
S* 0.0.0.0/0 [1/0] via 10.40.23.254
08-28-2012 07:40 PM
I see how to enable and disable the routing:
no ip routing
After removing the route directives that were added manually, I enbled routing with:
ip routing
I then see the following:
#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
10.0.0.0/22 is subnetted, 1 subnets
C 10.40.20.0 is directly connected, Ethernet0
08-28-2012 08:43 PM
Art
It appears that you are making progress in understanding how the IOS work for routing on Cisco routers. So congratulations on that.
In the most recent config you have only the locally connected subnet. So your router should be able to communicate with anything in the local subnet. But it would not communicate with anything in remote subnets.
In the post before that you have the locally connected subnet and a default route. This would allow your router to communicate with devices in remote networks.
I can not tell whether you still have a question for the forum. If you do still have a question then perhaps you can re-state what your question is. Then we may be able to find answers for it.
HTH
Rick
08-29-2012 11:36 AM
Thank you very much for the dialog. It helps a lot...
Though, I think that I continue to be clueless about my issue.
I think you may be suggesting that it should work now...
Should it work, now? Should I be able to ping my gateway at 10.40.23.254 ?
Should I be concerned with the message "Gateway of last resort is not set" ?
I am unable to make a ping work on 10.40.23.254.
Of course i can ping myself at 10.40.20.51
Any advice to make this device operate on the network and pingable from another host on the same subnet such as 10.40.20.74, would be appreciated.
many thanks!
09-04-2012 02:10 AM
Art
It seems that you did not understand my previous post, so let me try again in a slightly different way. The output in your previous post shows that the Ethernet0 interface is up and is configured with an IP address in a /22 network. You should be able to ping your gateway and the gateway should be able to ping your 2511.
However your 2511 will not be able to access anything outside of its local subnet. The message about gateway of last resort is not set indicates that your router has no route information for anything outside of the local subnet.. A Cisco router has two methods of learning about resources outside of its local subnet. The router can have static routes (frequently including a static default route) or it can run a dynamic routing protocol (such as RIP or EIGRP). It appears that your router is now not doing either of these. In earlier posts the configuration include this static default route:
ip route 0.0.0.0 0.0.0.0 10.40.23.254
If you put this back into the configuration (and assuming that ip routing is enabled) then you should be able to access resources outside of the local subnet.
HTH
Rick
09-04-2012 11:33 AM
Hi Rick,
Thank you for your patience and guidance. At this point I am wondering if I am in possession of some broken equipment? Could my AAUI transciever cause my problem? If I had two then I would swap and be more confident.
I inserted the static route.
Current config is the following:
LA-AS#sh startup-config
Using 824 out of 32762 bytes
!
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname LA-AS
!
logging rate-limit console 10 except errors
enable secret 5 $1$oH4m$afnnZjU0EF92dCJ.VVPq61
!
username admin password 0 admin1
ip subnet-zero
no ip finger
no ip domain-lookup
!
!
!
!
interface Ethernet0
ip address 10.40.20.51 255.255.252.0
no ip mroute-cache
!
interface Serial0
no ip address
no ip mroute-cache
shutdown
no fair-queue
!
ip classless
ip route 0.0.0.0 0.0.0.0 10.40.23.254
no ip http server
!
!
line con 0
logging synchronous
login local
transport input none
line 1 16
no exec
exec-timeout 0 0
no flush-at-activation
transport input all
line aux 0
logging synchronous
login local
line vty 0 4
logging synchronous
login local
!
end
Also enabled ip routing:
LA-AS#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is 10.40.23.254 to network 0.0.0.0
10.0.0.0/22 is subnetted, 1 subnets
C 10.40.20.0 is directly connected, Ethernet0
S* 0.0.0.0/0 [1/0] via 10.40.23.254
LA-AS#sh interfaces
Ethernet0 is up, line protocol is up
Hardware is Lance, address is 00b0.64fd.3ba5 (bia 00b0.64fd.3ba5)
Internet address is 10.40.20.51/22
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:03, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 1/75, 0 drops
5 minute input rate 0 bits/sec, 1 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
8864 packets input, 625440 bytes, 0 no buffer
Received 8864 broadcasts, 0 runts, 0 giants, 0 throttles
1 input errors, 0 CRC, 0 frame, 0 overrun, 1 ignored
0 input packets with dribble condition detected
258 packets output, 27504 bytes, 0 underruns(0/0/0)
0 output errors, 0 collisions, 5 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
09-05-2012 06:27 AM
Art
I have looked through the config and I do not see an obvious problem. And the fact that the show interface shows that the interface is up and up is encouraging. And the fact that there are input packets and output packets is also a good sign.
Based on this I do not think that your transceiver is faulty.
One other thing that might be helpful would be to post the output of show arp.
From what I see here it looks like it should be working. If there is something that is not working can you give us some clarification of what is the problem?
HTH
Rick
09-05-2012 01:28 PM
Hi Rick,
I can't thank you enough for your time. I appreciate how you share your experience to help.
Here is arp info and some pings too:
LA-AS#sh arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 10.40.20.51 - 00b0.64fd.3ba5 ARPA Ethernet0
Internet 10.40.23.254 3 2c21.72a1.a181 ARPA Ethernet0
Internet 10.40.20.250 0 0030.4865.4208 ARPA Ethernet0
LA-AS#ping 10.40.20.51
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.40.20.51, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms
LA-AS#ping 10.40.20.250
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.40.20.250, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
LA-AS#ping 10.40.23.254
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.40.23.254, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
LA-AS#
09-05-2012 03:45 PM
Art
This output is quite surprising. The good news is that the arp output does demonstrate that at layer 2 you are communicating (and I believe this demonstrates that your transceiver is not faulty). The surprising thing is that at layer 3 there seems to be a problem.
One thing that might help would be if you post the output of show cdp neighbor detail. This is another way of demonstrating that the interface is communicating.
One thought that occurs to me is that some devices have firewalls (or in the case of routers may have access lists) that do not allow response to ping. So one question would be whether other devices on this network can ping to 10.40.23.254 or to 10.40.20.250. Another question would be whether these devices can ping to your 2511.?
And just a comment - you have been giving us output of show startup-config. It would be slightly better if it were the output of show running-config. Most of the time the two outputs would be the same. But in the instances where they are different it is the running-config that is what the router is actually doing.
HTH
Rick
09-05-2012 06:59 PM
Hi Rick,
This is really fantastic to learn these details from you! There is way more to networking than a lot of engineers even bother to think about. Most (including me) just plug a cable and take it all for granted! (until situations like these) lol!
Due to weirdness on this network (e.g. ssh sessions that hang for no reason after 10 minutes) I've been suspicious of some kind of networking problem for months but of course IT says everything is fine. Is it no surprise that ssh keepalive is their go to response. lol!
Hmm... Should I start a new discussion thread with subject "what's wrong with my company's network?" Seriously though... I can start a new thread if appropriate.
LA-AS#show cdp neighbor detail
-------------------------
Device ID: 6c9cedf72aaa
Entry address(es):
IP address: 10.40.23.7
Platform: Cisco SG200-26 (PID:SLM2024T)-VSD, Capabilities: Switch IGMP
Interface: Ethernet0, Port ID (outgoing port): gi11
Holdtime : 153 sec
Version :
1.2.7.76
advertisement version: 2
Native VLAN: 1
Duplex: half
LA-AS#sh ru
LA-AS#sh running-config
Building configuration...
Current configuration : 824 bytes
!
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname LA-AS
!
logging rate-limit console 10 except errors
enable secret 5 $1$oH4m$afnnZjU0EF92dCJ.VVPq61
!
username admin password 0 admin1
ip subnet-zero
no ip finger
no ip domain-lookup
!
!
!
!
interface Ethernet0
ip address 10.40.20.51 255.255.252.0
no ip mroute-cache
!
interface Serial0
no ip address
no ip mroute-cache
shutdown
no fair-queue
!
ip classless
ip route 0.0.0.0 0.0.0.0 10.40.23.254
no ip http server
!
!
line con 0
logging synchronous
login local
transport input none
line 1 16
no exec
exec-timeout 0 0
no flush-at-activation
transport input all
line aux 0
logging synchronous
login local
line vty 0 4
logging synchronous
login local
!
end
===============================
Regarding ping from other hosts...
I do not have access to gateway, 10.40.23.254
Never a successful ping to the AS2511 (10.40.20.51) from:
10.40.20.250
10.40.20.74
$ ping 10.40.20.51
PING 10.40.20.51 (10.40.20.51) 56(84) bytes of data.
From 10.40.20.250 icmp_seq=2 Destination Host Unreachable
From 10.40.20.250 icmp_seq=3 Destination Host Unreachable
From 10.40.20.250 icmp_seq=4 Destination Host Unreachable
^C
--- 10.40.20.51 ping statistics ---
4 packets transmitted, 0 received, +3 errors, 100% packet loss, time 3000ms
$ ping 10.40.20.51
PING 10.40.20.51 (10.40.20.51) 56(84) bytes of data.
From 10.40.20.74: icmp_seq=1 Destination Host Unreachable
From 10.40.20.74: icmp_seq=2 Destination Host Unreachable
From 10.40.20.74: icmp_seq=3 Destination Host Unreachable
From 10.40.20.74: icmp_seq=4 Destination Host Unreachable
^C
--- 10.40.20.51 ping statistics ---
4 packets transmitted, 0 received, +4 errors, 100% packet loss, time 3000ms
But yet, nearly all other hosts on this network can ping amongst themselves...
for example from 10.40.20.74
$ ping 10.40.20.250
PING 10.40.20.250 (10.40.20.250) 56(84) bytes of data.
64 bytes from 10.40.20.250: icmp_req=1 ttl=64 time=0.311 ms
64 bytes from 10.40.20.250: icmp_req=2 ttl=64 time=0.243 ms
64 bytes from 10.40.20.250: icmp_req=3 ttl=64 time=0.246 ms
^C
--- 10.40.20.250 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2000ms
rtt min/avg/max/mdev = 0.243/0.266/0.311/0.036 ms
$ traceroute 10.40.20.250
traceroute to 10.40.20.250 (10.40.20.250), 30 hops max, 60 byte packets
1 qa250.TLD (10.40.20.250) 0.296 ms 0.250 ms 0.222 ms
Thanks again for your assistance...
It is very helpful!
-AZ
09-06-2012 04:39 AM
AZ
Since the discussion is now about much more than the Ethernet interface of your 2511 it might be justified to start a new discussion. But I am willing to continue with this one for a bit since it is already in process and is developing some context that we might need to repeat in a new discussion. So it is your choice.
There are a couple of things that I would like to follow up from the most recent post.
- the cdp neighbor shows that you are connected to a SG200 switch with address 10.40.23.7. So lets see if your 2511 can ping it.
- if the ping to 10.40.23.7 fails, then follow it immediately with a show arp. I would like to see if arp succeeded or not.
- what was the IP address and what is the subnet mask of the device from which you attempted to ping the 2511? If they are in the same subnet I would have expected the ping to be directly between the devices. But you got a response from 10.40.20.250 that your address was not reachable. That implies that your source was at least one hop away. So I would like to know what it is.
- And i am curious why 10.40.20.250 thinks your 2511 is not reachable. It was showing up in your arp table, so I would assume that you should have been in its arp table. I am beginning to wonder if the SG200 is doing something, or is perhaps configured in a way that isolates your 2511. Do you know anything about the SG200 or have any access to it?
HTH
Rick
09-06-2012 12:58 PM
LA-AS#ping 10.40.23.7
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.40.23.7, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
LA-AS#show arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 10.40.20.51 - 00b0.64fd.3ba5 ARPA Ethernet0
Internet 10.40.23.7 0 6c9c.edf7.2aaa ARPA Ethernet0
Internet 10.40.23.254 1 2c21.72a1.a181 ARPA Ethernet0
Internet 10.40.20.250 2 0030.4865.4208 ARPA Ethernet0
LA-AS#
Yes, same subnet. I attempted to ping the AS2511 from both: 10.40.20.74/22 and 10.40.20.250/22
Note that part of my infrastructure which I inherited intermingles with corp IT when my switches uplink into a Juniper EX3300.
I will attempt to describe the interconnects.
Your focus on the SG200 switch is an excellent idea. I continue to have issue with it which I worked around in the following way.
At first, I could not get a link light to illuminate on the SG200 port into which the AS2511 was connected regardless of how I twiddled the port config (e.g. 10M, Half-Duplex). Note, the link light on the AAUI connector would illuminate even though the 10M/half configured port on the SG200 would not illuminate.
So, to make that problem go away, I inserted an old consumer grade Netgear DS104 dual-speed hub between the AS2511 and the SG200 essentially using it to uplink to the SG-200. That made the link light on the SG200 illuminate and the protocol to come up according to the AS2511 sh interfaces.
With that "disclosure" out of the way (lol), here is the interconnects:
AS2511 <=> DS104 <=> SG200 <=> EX3300 <=fiber=> Unknown <=> 10.40.20.250
Whereas, the host 10.40.20.74/22 is connected as:
DS104 <=> 10.40.20.74
Of course, 10.40.20.74 and 10.40.20.250 can talk freely.
Please note... I did not design this network topology so I cannot claim the credit/fame for the reason that the host 10.40.20.250 is in different physical location than my datacenter with the AS2511 and everything else in this discussion. lol.
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