Cisco 881W with smart switch issue

[bryanlooi]

I cant seem to connect my cisco 881W to a 3COM smart switch. The switch does not seem to receive any dhcp IP address that is given by the router when devices are conneceted to the switch. However if I use an unmanaged switch, i can get an Ip address. I am wondering if there is a onfiguration that is needed to ensure that the router can be used with a smart switch that already is set to be used with DHCP.

These are the current config

Any help would be grateful.

version 15.2

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname yourname

!

boot-start-marker

boot-end-marker

!

!

logging buffered 51200 warnings

!

no aaa new-model

!

!

!

ip dhcp excluded-address 10.10.10.51 10.10.10.254

!

ip dhcp pool ccp-pool

import all

network 10.10.10.0 255.255.255.0

default-router 10.10.10.1

dns-server 202.188.0.133 8.8.8.8

lease infinite

!

!

!

ip name-server 202.188.0.133

ip name-server 8.8.8.8

ip cef

no ipv6 cef

!

!

interface FastEthernet0

no ip address

!

interface FastEthernet1

no ip address

!

interface FastEthernet2

no ip address

!

interface FastEthernet3

switchport mode trunk

no ip address

!

interface FastEthernet4

ip address dhcp

ip nat outside

ip virtual-reassembly in

duplex auto

speed auto

!

interface Wlan-GigabitEthernet0

description Internal switch interface connecting to the embedded AP

no ip address

!

interface wlan-ap0

description Service module interface to manage the embedded AP

ip unnumbered Vlan1

!

interface Vlan1

ip address 10.10.10.1 255.255.255.0

ip directed-broadcast

no ip proxy-arp

ip nat inside

ip virtual-reassembly in

ip tcp adjust-mss 1452

!

ip forward-protocol nd

ip http server

ip http authentication local

ip http secure-server

ip http timeout-policy idle 60 life 86400 requests 10000

!

ip nat inside source list 199 interface FastEthernet4 overload

!

access-list 199 permit ip any any

no cdp run

!

!

!

line con 0

login local

no modem enable

line aux 0

line 2

no activation-character

no exec

transport preferred none

transport input all

stopbits 1

line vty 0 4

privilege level 15

login local

transport input telnet ssh

line vty 5 15

access-class 23 in

privilege level 15

login local

transport input telnet ssh

!

scheduler allocate 20000 1000

!

end

[John Blakley]

Does the 3com have vlans configured on it? The only vlan that needs to be on there is vlan 1, and it needs to be untagged.

HTH,
John

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[bryanlooi]

Thanks for the reply John,

But the 3COM switch is already on Vlan 1, Untagged. I have restored the configuration of the switch to factory default, but the problem still exist.

However i think that it is a VLAN issue as an unmanged switch does not seem to have a problem.

On the router, must vlan be turned on? It seems so. The interface for FE0,1,2,3 are assigned to vlan 1 with the DHCP Pool. Is there away i can disable this. On my cisco configuration pro software, the FE LAN 0,1,2,3 does not have an ip address. But i can use the internet. I think the VLAN is assignning it to them.

Any help would be appreciated.

[John Blakley]

Are you saying that hosts connected to the switch don't get an address from your Cisco router? The configuration of the router is fa0 - 3 are members of vlan 1, and interface fa4 is a wan port, so the configuration is correct for that part of it. If you connect a normal switch, dhcp works? What port are you connecting the switch to from the 3com?

HTH,
John

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[bryanlooi]

Yes, that is correct. Any computers connected to the 3COM switch does not get an ip adrress from the cisco router. However if i connect a normal oswitch which is an unmanaged Dlink switch, i can get an IP address and use the internet as normal. Im connecting the 3COM switch to port 1. And the unmanaged to port 3.

Any help would be appreciated

Bryan

[John Blakley]

Can you post "sh int fa1" and can you post the configuration of the switchport of the 3com that you're connected to? Is this 3com a l2 or l3 switch? Do you have a model number?

HTH,
John

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[bryanlooi]

What do you mean by sh int fa 1?

Again what do you mean the switchport configuration of the 3COM that youre connected to. Do you mkean the configuration of the 3COM itself or what?

This is a l2 switch. Its a 3COM baseline 2226 SFP Plus.

Thanks.

[John Blakley]

Are you telnetted or consoled into the router? If so, run that command "sh int fa1" and copy/paste the results. If you're using a web browser to manage the router, I'm not versed in that enough to help walk you through it unfortunately.

Each port will have a configuration on the switch and the router. I wanted to see the configuration of the 3com switch to see how it was configured.

HTH,
John

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[bryanlooi]

Yes, I am connected via telnet. This is the results for that command

FastEthernet1 is up, line protocol is down

  Hardware is Fast Ethernet, address is c067.af1c.4bc7 (bia c067.af1c.4bc7)

  MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Auto-duplex, Auto-speed

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input never, output never, output hang never

  Last clearing of "show interface" counters never

  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 0 bits/sec, 0 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     0 packets input, 0 bytes, 0 no buffer

     Received 0 broadcasts (0 multicasts)

     0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog, 0 multicast, 0 pause input

     0 input packets with dribble condition detected

     0 packets output, 0 bytes, 0 underruns

     0 output errors, 0 collisions, 2 interface resets

     0 unknown protocol drops

     0 babbles, 0 late collision, 0 deferred

     0 lost carrier, 0 no carrier, 0 pause output

     0 output buffer failures, 0 output buffers swapped out

The 3COM switch is set to factory default.

Im sorry for asking some basic questions. I am new to this. Everyhelp is appreciated.

Thank you

[John Blakley]

No problem. The interface is up/down at the moment. Can you check the port of the 3com to make sure it's in Auto/Auto? Also, do you have a crossover cable that you can use to connect this switch to the router? The 3com may not support auto-mdix and needs a crossover cable to make a connection. You did have it connected at the time you do the above command correct?

HTH,
John

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[bryanlooi]

Yes, the 3COM switch are all auto MDI/MDIX ports. And i also tried using a cross over but still it does not work.

No, to get the results from the command i took off the 3COM switch and plugged it directly to the router. If i went through the switch i cant get a connection as there is no IP.

Im totally confused why this is happening as my prvious cisco was a 871W. and it worke dperfectly fine. The only difference was that last time i did not need to set a vlan to the FE 0,1,2,3 and the FE0,1,2,3 has an ip directly. Not too sure what the difference is here.

The 3Com switch is set to a static ip of 169.254.166.34. using a DHCP address also does not work. But if i connected straight from my cable modem to the 3Com switch it works. Currently my set up is Cable modem > Cisco Router > 3Com Switch which does not work but previously on the 871W it did. But if i did cable modem > 3Com switc. it will work.

Any help would be appreciated.

Thanks

[John Blakley]

Do you have another 3com that you could test? It's not a vlan issue with the Cisco or you wouldn't get an address when connected directly to it or with the unmanaged switch.

Out of curiosity, what port are you connecting to on the 3com? Do you at least get link lights when connected?

HTH,
John

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[bryanlooi]

No i dont have another 3COM switch. Because on the 871W it works, but on the new 881W it deosnt. And it will work if connected directly do a DLINK cable modem. Only doesnt work when connected to the cisco.

Im connecting FA1 to port 1 of the 3COM. Ive swapped to diiferent ports also but it still does not work. And yes. I get the activity lights when connected. Only not an IP address.

This is extremely weird.

Any help would be appreciated.

Thanks

Bryan.