Switch WS-C3750G

[Walter Astori]

                   I have 2 switch 370 in stack. Random the switch is operational, but is impossible connect to switch in ssh or telnet

[chandra_rc16]

What type of error are you getting, while trying to telnet or ssh ? Can you post the output?

Regards,
Chandu

[Walter Astori]

            I have configured switch to log information message to syslog, but there isn't message of error. When i try to connect to switch i receive connestion refused. I try to analyze the switch with nmap but there isn't open port tcp on 22 or 23. The switch is operational but for my is impossible establish a connection.

[chandra_rc16]

Are you getting like the below one?

Regards,
Chandu

[Walter Astori]

My answer is :

sfwus01p:/var/lib/tftpboot# telnet 192.168.0.17

Trying 192.168.0.17...

telnet: Unable to connect to remote host: Connection refused

The only solution is reboot hardware (unplugged electrical cable and plugged electrical cable). I think to upgrade my IOS version, if there isn't none solution.

[chandra_rc16]

Can you post a ping and traceroute to the device your tyring to telnet ...from

sfwus01p:/var/lib/tftpboot#  ?

Regards,
Chandu

[Walter Astori]

sfwus01p:/var/lib/tftpboot# ping 192.168.0.17

PING 192.168.0.17 (192.168.0.17) 56(84) bytes of data.

64 bytes from 192.168.0.17: icmp_seq=1 ttl=255 time=0.479 ms

64 bytes from 192.168.0.17: icmp_seq=2 ttl=255 time=0.472 ms

64 bytes from 192.168.0.17: icmp_seq=3 ttl=255 time=2.21 ms

64 bytes from 192.168.0.17: icmp_seq=4 ttl=255 time=9.60 ms

^C

--- 192.168.0.17 ping statistics ---

4 packets transmitted, 4 received, 0% packet loss, time 3003ms

rtt min/avg/max/mdev = 0.472/3.193/9.609/3.771 ms

sfwus01p:/var/lib/tftpboot# traceroute 192.168.0.17

traceroute to 192.168.0.17 (192.168.0.17), 30 hops max, 40 byte packets

1  192.168.0.17 (192.168.0.17)  0.516 ms * *

sfwus01p:/var/lib/tftpboot#

[Amit Singh]

As you mentioned, if you have these already configured, you might be hitting a cosmetic bug. What is the IOS version your are running? I would try to upload a new one on the stack and see if that resolves the issue.

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00804799d7.shtml

[Amit Singh]

Walter, Please can we have a loo at your switch configs? Would it be possible for your paste it here if you have old one handy or if you could console and get it for us. I seems like you dont have telnet or SSH configured on the boxes.

Cheers,

-amit singh

[Walter Astori]

The version of Cisco IOS is 12.2(44) SE.Here my configuration for authentication :

aaa new-model

!

!

aaa authentication login default local group tacacs+ none

aaa authentication login Console local enable

aaa authorization exec default local group tacacs+

aaa authorization commands 15 default local group tacacs+

aaa authorization commands 15 Console if-authenticated

aaa accounting commands 15 default start-stop group tacacs+

aaa accounting network default start-stop group tacacs+

aaa accounting connection default start-stop group tacacs+

aaa accounting system default start-stop group tacacs+

tacacs-server host 172.16.0.5 key 7

tacacs-server host 172.16.0.6 key 7

tacacs-server host 172.16.0.7 key 7

tacacs-server directed-request

line con 0

password 7

line vty 0 4

transport preferred ssh

line vty 5 15

transport preferred ssh

[Leo Laohoo]

telnet: Unable to connect to remote host: Connection refused
 
The only solution is reboot hardware (unplugged electrical cable and plugged electrical cable). I think to upgrade my IOS version, if there isn't none solution.

Ok, console into the switch.  Post the following command outputs:

1.  sh version;

2.  sh proc cpu | ex 0.00

[Walter Astori]

It's strange. If i connected the console to switch 2 the message is "Low memory" and i can't connect. If i connected the console to switch 1 there isn't message, but i don't have a prompt for login. The switch are monitored by mrtg and mrtg visualize the following data :

	Max	Average	Current
Used	77.0 MRAM (30.1%)	77.0 MRAM (30.1%)	77.0 MRAM (30.1%)
Free	2093.3 kRAM (0.8%)	2080.4 kRAM (0.8%)	2081.3 kRAM (0.8%)

[Leo Laohoo]

It's strange. If i connected the console to switch 2 the message is "Low memory" and i can't connect

Forget it.  This information is more than what I need. 

What IOS are you running?  When you console into an appliance and you're greeted with "Low memory" this is an indication that the IOS you're using is or has a CPU/Memory hog bug. 

[Walter Astori]

The version of IOS is 12.2(44)SE. I search on Internet if there is a memory upgrade for 3750, but the memory upgrade for switch start by 4000/4500 series. This stack is connected by 2 uplink to another stack switch of 3750 and by 2 uplink to another stack switch of 3750 (Total i have 3 stack switch of 3750 configured in spanning-tree environment). Also the another stack of 3750 switch has the same issue (after many week of switch up and running, i can't connect to the switch with telnet or ssh, i think for the same problem, low memory).All the stack switch have the same version of IOS.

The spannig-tree is configured in rapid-pvst mode with one stack primary for some vlan and another stack secondary for some vlan.

For now i can't upgrade IOS version of switches, which are the alternative solutions ?

[Leo Laohoo]

Upgrade the IOS of your entire stack.  Go to 12.2(55)SE8 as it's more stable than what you are currently using.  It's more stable by A MILE!