IOS, or Internetwork Operating System, is the operating system employed by most Cisco devices. It is also used to refer to the command line shell that is used to configure Cisco devices.
4
votes
1answer
124 views
How can I reasonably verify my QoS configuration is working?
Context
I've deployed a standard QoS config to a customer site running a Cisco 891 router with IOS 15.1(4)M4. The WAN link is a single ADSL2+ link (24/1Mbps) connected to FE8.
I've previously tested ...
3
votes
0answers
68 views
SCP lost connection
Occasionally I have an issue when I try to SCP a file to one of our Cisco devices. When the connection starts, it immediately drops and says "lost connection". I've had this happen when there wasn't ...
1
vote
1answer
62 views
Cisco 3548XL VLANs, no router
I am working on a project currently in our lab. I have 1 3548XL with an uplink to our telco.
Most of my Cisco experience is on the 6500 platform so I am used to having L3 features at my disposal. Is ...
9
votes
3answers
174 views
Is it possible to disable a single DHCP pool in IOS?
I am working on a Cisco L3 switch where most of SVIs are having ip helper-address configured for DHCP relay but also a couple of DHCP pools have been configured in the switch itself to serve dynamic ...
3
votes
1answer
170 views
Line protocol is down on Cisco Router / IOS 12.2
I have this error on a Cisco router running IOS version 12.2.
This coincide with an error received on our alarming system saying that on this router we have an interface with "line protocol down". ...
5
votes
2answers
151 views
Multiple WANs/Out-of-band (Cisco 1900)
I've got a Cisco 1900 router which connects to the Internet using a primary and a secondary WAN connection.
When the primary connection is up, all traffic use this link. When the primary connection ...
5
votes
1answer
154 views
What is the difference between “permit tcp any any eq telnet” and “permit tcp any eq telnet any”?
I'm a CCNA student and during a LAB I found that for some rules on an incoming extended ACL using a rule like permit tcp any any eq (protocol) would work fine while on other rules I needed to use the ...
3
votes
5answers
298 views
Automating Cisco IOS Config Backups using Plink
Anyone ever done this before? Trying to use plink.exe to execute a commands.txt file remotely and pull the running config. Unfortunately using the -m argument and specifying a simple command.txt file ...
11
votes
2answers
170 views
Do unused Cisco IOS features take up RAM/CPU resources?
For example, let's compare IP Base vs. Advanced Enterprise Services. Let's say you have advent installed, but you're only actually using the features relevant to ipbase. Other than flash memory space, ...
6
votes
1answer
88 views
Globally disable QoS on Cisco 3750 in production
I suspect some issues with faulty QoS settings on a 3750 stack running in a 24x7 environment. The 3750 mainly routes between vlans on a lan segment. Since it is a lan device (not terminating any wan ...
5
votes
2answers
105 views
Metro Ethernet settings on Customer devices
I am about to connect three remote sites to the main office by means of an metro ethernet provided by a service provider. The sites are connected by means of l3 and running OSPF on the connecting ...
12
votes
3answers
333 views
BGP signalled MPLS issues
I am having an issue getting a VPLS up using an ME3600x with 15.3(2) and BGP signalling.
@yelfathi and @packettalk have pointed me down the correct route but not sure how to resolve it.
I have 2 ...
6
votes
1answer
72 views
Configure External Interface for DHCPv6 client on Cisco IOS
What are the necessary steps to configure IOS 12.4(25f) to support IPv6? Comcast is the ISP, and I'll be using a Server 2012 box for internal DHCPv6.
I'll need to grab a DHCPv6 address from Comcast ...
7
votes
1answer
174 views
Cisco IOS built-in SSH client default version
You issue the command ssh 192.168.97.97 from a IOS device and the destination IOS router/switch SSH server is accepting both SSH versions. Being that you did not specify a version to use on the SSH ...
4
votes
3answers
240 views
AAA/TACACS+ password on Cisco switch always fails at second password prompt
Whenever logging into a network device using AAA/TACACS+, if I fat-finger the password prompt after the username prompt, the second password prompt always fails even when the password is correct. I ...
13
votes
3answers
426 views
What factors drive a Cisco IOS upgrade?
In order of preference/priority, what factors do you consider in driving an upgrade (or downgrade) with Cisco IOS? If no compelling factors exist, how long would you allow a particular version of IOS ...
-5
votes
2answers
97 views
auto-summary / no autosummary output [closed]
My class book (its in russian unfortunately) says that auto-summary command should output some info upon execution, but the only place where i could run it was rip config mode (otherwise it just ...
6
votes
3answers
165 views
Why does “show adjacency” take so long to run?
Why does the "show adjacency" command take so long to run (in the order of minutes) on Cisco IOS Software, 7200 Software (C7200P-SPSERVICESK9-M), Version 12.4(4)XD5, RELEASE SOFTWARE (fc1)? The ...
7
votes
5answers
287 views
How can I speed up CLI typing in Cisco IOS using shortcuts?
I know we can use auto-completion (tab key) and abbreviated commands (such as sh ip int bri) to speed up typing.
However, I'm still not satisfied with typing crypting chains such as sh ip dh sn bi | ...
5
votes
1answer
252 views
What is the NO PAYLOAD ENCRYPTION version of the IOS software?
When looking at the downloads available on the Cisco site, they have a regular version of the file and a NO PAYLOAD ENCRYPTION version. What is the difference? And why would one choose one over the ...
-5
votes
3answers
146 views
Need some standard configurations for Cisco 1900 series router [closed]
Just bought a Cisco 1921 router but I'm new to Cisco. Been having a hard time configuring it, what are some standard configurations for these? I have a L3 switch that will be connected to it and using ...
22
votes
20answers
3k views
How can I see which switchports are not in use?
On a large Cisco Catalyst switch stack, almost all switchports are patched. I need to identify the ports, which are not in use, for connecting further devices.
Following switchports, cabling, patch ...
12
votes
4answers
834 views
How can I capture traffic on Cisco IOS switches?
For investigating a problem in client to server communication, I need to capture packets for analysis. However it's not allowed to install a packet analyzer, such as Wireshark or tcpdump, on client or ...
5
votes
2answers
330 views
What is Dec MOP and how to disable it?
Performing a packet capture I keep seeing strange "DEC MOP Remote Console" frames:
No. Time Source Destination Protocol Info
141 83.557841 Cisco_57:62:a0 ...
