Questions tagged [cisco-ios]

For discussion about Cisco's Internetwork Operating System - Cisco IOS

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1answer
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Specific DHCP pool on specific interface - IOS

Is it possible for a specific interface to only allow access to specific dhcp pools? This is assuming a cisco router(IOS) with dhcp server capabilities. E.g. For some router, hosts on fa0/0 can ...
6
votes
2answers
461 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 ...
6
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1answer
590 views

Bandwidth limit Cisco 3400 ME problem

I want to limit bandwidth (speed) of interface of Cisco 3400 ME switch. I did these: policy-map parent class class-default shape average 64000 And in gi0/2 interface I apply it: service-policy ...
6
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2answers
1k views

Why is Cisco enforcing X:X:X:X::X for link-local addresses when the standard says FE80:/10?

This document shows that you can use one of these options: interface type/number ipv6 address ipv6-prefix/prefix-length eui-64 ipv6 address ipv6-prefix/prefix-length link-local <------...
6
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3answers
329 views

Network Address Translation fundamentals

Could someone please help me understand the concepts of NAT? I thought I understood how this works, but I'm confused about there being two public addresses, as opposed to just one public internet ...
6
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1answer
6k views

Cisco 1200 AP, client information from CLI

I'm working with several cisco 1200 series APs, trying to get relevant client information off of them. It would be helpful to see RSSI and SNR for individual clients connected, but I am unable to ...
6
votes
1answer
393 views

Is it possible to have ranges in two octets in an ACL / object-group

I'm trying to find out if there is a "clean" way to do this. I need to setup a ACL on a FWSM that effects devices over multiple subnets. The structure looks like this: 10.10.1-254.1-15 I could do: ...
6
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1answer
3k views

console connection via Cisco router's AUX port

my question is simple: if I am logged into a Cisco router via console or ethernet in priviledged mode, is there a command to initiate a connection through the local AUX port to a nearby console port ...
6
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1answer
7k views

Rolling Stack Upgrade on a Catalyst 3850

I'm looking to do an IOS upgrade on a two Switch 3850 stack, with minimum downtime. As our servers all have redundant uplinks to each switch, it would be preferable to reload each stack member ...
6
votes
2answers
3k views

Policy Based Routing for VPN connections with VPN Client configuration

We have a Cisco 2800 router in our company that also serves as a VPN server. We use the VPN Client to connect to our corporate network (pls don't laugh, I know that it is very obsolete but I haven't ...
6
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3answers
3k views

OSPF default route, 2 routers connecting to ISP

At work, we have a network with 2 routers connected to ISPs, and other routers in our internal network like this: ISP ISP |(BGP) |(BGP) R1 ...
6
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1answer
4k views

How to view default authentication method for different lines(cty, vty, aux, tty) in IOS?

For example if I enable AAA(aaa new-model) in IOS router with default configuration and try to log in over console line(cty), then there is no authentication. However, if I try to log in over telnet(...
6
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1answer
9k views

Why do DHCP servers lease IP address based on Option-61 (Client-ID)?

Why do DHCP servers (specifically Cisco) use "Client-ID Options", not the CHADDR (client MAC) in the DHCP request, for static binding? From: Configuring DHCP All DHCP clients send a client ...
6
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1answer
197 views

Cisco 3620, installing nm-2fe2w

Is the WIC plug and play or are there commands that I need to run? The router is not showing the interfaces. I tried using the sh diag and it didn't show anything.
6
votes
1answer
832 views

On the Cisco AIR models, what is the definition of radio reset code 71?

We are using the Autonomous mode... Cisco IOS Software, C1040 Software (C1140-K9W7-M), Version 15.2(4)JA1, RELEASE SOFTWARE (fc2) ap#sh controllers do1 radio-reset Last radio reset code: 71 Radio ...
6
votes
1answer
4k views

Cisco OSPF type 5 /32 routes in database, but not in routing table

Our network runs OSPF for IPv4 on Cisco hardware. The following image shows the relevant topology: Topology Problem Statement We have a Cisco ASA firewall, which also is the VPN gateway for ...
6
votes
1answer
6k views

AAA Authorization Timeout

Log into a Cisco IOS device with TACACS Authorization enabled Do a command that causes the device to lose access to the TACACS server Enter a command that requires TACACS Authorization By default, ...
5
votes
1answer
2k views

How to Disable telnet on Cisco switch totaly?

I have disabled telnet on Cisco 2960G switch by putting: line vty 04 transport input ssh but now when I try telnet to the switch I get message saying,password required but not set I am wondering ...
5
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3answers
3k views

Configuring OSPF on two directly connected routers which are in different areas

I want to configure OSPF on the topology below. The problem is when I connect two routers to each other and when I config one router to area 0 and another one to area 1, they don't see each other as ...
5
votes
1answer
6k views

Cisco 2960 switch will not recognize new TACACS+ commands

I'm trying to add tacacs info to a switch. However, I'm unable to use the new tacacs commands, even though the switch tells me to. WS-C2960-24PC-L - Version 15.0(2)SE5 switch(config)#tacacs-server ...
5
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3answers
5k views

Privilege configuration on cisco switch

I have a Cisco switch who have an user configured with privilege level 3 configured as below ! the user can configure an interface privilege configure level 3 interface privilege exec level 3 ...
5
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2answers
203 views

Carrying remote VLAN via 2 routers to the local gateway

I have a serverA (192.168.15.1) from site A and VLAN is 15, however the VLAN 15 gateway is set at site B (192.168.15.254). There are two ISP routers as a metro role to connect each other by subnet ...
5
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1answer
6k views

When and where to use Spanning-Tree (Portfast)

The tl;dr, in which scenario (switch-to-host, or switch-to-switch) do I use spanning-tree portfast or spanning-tree ...? We had a catastrophic network outage today. My first question to my boss was "...
5
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1answer
1k views

Why is option 82 required for DHCP when you use `ip verify source port-security`?

Learning about security features on Cisco switches and came across the requirement to use option 82 with DHCP when you enable ip verify source port-security on an interface. How is this different ...
5
votes
1answer
243 views

malloc failures and ARP packed on a Cisco 2901

I have a 2901 between a network and the internet. It shipped with the routing defined as follows. ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/1 Using the interface like this instead of an IP struck ...
5
votes
1answer
2k views

Best practice for advertising routes in BGP

For connect some customer we want to advertise only one network out and different networks in they provide us. For this I read about route-map and advertising-map feature in Cisco Docu. For example ...
5
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2answers
1k views

Any reason NOT to use VTP Pruning

I have inherited a network. I have 12 separate sites, all of which have at least 10 vlans. Each site is it's own VTP domain. I have an MPLS ethernet handoff into a switch at each site. From each ...
5
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3answers
37k views

Cisco Router Telnet Connection Refused

I have a cisco 1941 router just configured but no matter how I go about configuring the telnet, it seems not to work. It has interfaces already set up and systems can browse through it in the office....
5
votes
1answer
5k views

https url filtering on Cisco ASA 5520

I'm aware that you can use the ASA's URL filtering to filter URLs being accessed with regular expressions, but I'm curious if there is a way to filter which URLs can be accessed from the Internet to ...
5
votes
1answer
479 views

Why can't we find wccp on 3550 cisco L3 switch?

I'm trying to use wccp (Web Cache Communication Protocol) on 3550 cisco switch, the problem is that I can't find wccp: I can't do this command: switch(config)#ip wccp .... or switch#sh ip wccp ...
5
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1answer
14k views

IOS - Nat from a VRF to WAN interface in global routing table

Trying to get my head round how best to achieve the above In essence we have s speed test server that is available in the CPE's global routing table , that we would like the customer in VRF X to test ...
5
votes
2answers
858 views

QoS shaper, shapes traffic without dropping packets?

I have a problem with my QoS policy, or I should better say, I have a problem understanding how my policy manages to achieve what ask of it without dropping a packet! Here is the scenario: We have ...
5
votes
1answer
498 views

Cisco 3850-24p stable firmware 16.x.x

Have a query towards the 3850 series switches. Currently making a plan to upgrade a few remote sites from old, stable and steady 3650-24ps (eol awhile back) to 3850-24p. Nothing fancy to support, 1 ...
5
votes
1answer
185 views

What happens at the hardware level of a router when a packet is received and eventually triggers a process like ARP?

Please let me know where the gaps in my understanding are. There are many gaps, so please do not hesitate to fill them in or correct them. To my knowledge, what happens on the hardware level when ...
5
votes
2answers
296 views

Finding what devices are interconnected

I read about CDP - which says its a cisco protocol. It lists devices that are connected to each other. But if i don't have all cisco vender, how can I see what connects where? I have cisco router R1 ...
5
votes
2answers
1k views

Distinguish between router reload and “sysUpTime” SNMP counter wrap

If I poll over SNMP for example Cisco IOS interface ifHCInOctets counter and last reading is lower than previous reading, then I know that either the device has reloaded, ifHCInOctets counter has ...
5
votes
1answer
1k views

Consoled into Nexus 5596 and can't SSH or Ping directly attached servers - No route to host

How can I SSH to my Servers from Cisco IOS. My only current access to router is via console port.
5
votes
1answer
2k views

Cisco RIP - set metric for interface or network

In a network of Cisco routers, all running RIP, is it possible to set the hop count of an interface (or network)? The idea is to use the (artificial/adminstrative) hop count as means to do simple ...
5
votes
1answer
14k views

How To Limit a VLAN to a Specific Bandwidth Quota

I have a Cisco Router 1900 series and I would like to limit the bandwidth used by a subnet/subinterface. This subnet/subinterface (192.168.10.*) uses most of the bandwidth making it useless for other ...
5
votes
1answer
2k views

Cisco process memory usage

I am trying to monitor a Cisco process memory usage. This is what I get with the command line: show system internal processes memory | inc PID|ipfib PID TTY STAT TIME MAJFLT TRS RSS ...
5
votes
1answer
2k views

Controlling route-map distribution with 'match interface' in EIGRP

I have a "Tun0" interface over which I speak EIGRP. On this same router I have a "Vlan1" interface. What i'd like to do is speak only of the interfaces that pass a route-map, e.g. route-map foo ...
5
votes
1answer
412 views

Hardening Cisco router on Internet-MANAGEMENT PLANE

I need confirmation that I understood the Cisco manual right. So my network is like this: ISP_RTR ---x.x.x.x/30--- Perimeter/Edge_RTR ---y.y.y.y/30--- FW1 --- DMZ1 ...
5
votes
2answers
1k views

Cisco IOS - Is it possible to change severity level of a single syslog message?

On an ASA I can change the severity of a single syslog message by doing this: logging message 713120 level notifications Is there a way to do this on a Cisco Router running 15.1 code? I am only ...
5
votes
1answer
637 views

Enable traps on FIB (Forwarding Table) changes

I've been working for weeks to enable sending traps for FIB changes on our Cisco 2600 router. I finally found this command is responsible for that: snmp-server enable traps cef peer-fib-state-change ...
5
votes
2answers
237 views

Limiting rate of traffic to a really low level

I am using Cisco 1921 routers. I would like to configure them so as to limit the rate at which outbound data can flow. The kicker is that I want this rate limit to be quite low, say 1000 bytes per ...
5
votes
2answers
11k views

Addition of new switch to an existing 3850 stack

I have a existing switch stack with 4 switches in the stack (all of them are 3850). Switch Ports Model SW Version SW Image Mode ------ ----- ----- ----...
5
votes
1answer
2k views

Cisco ASA multiple dynamic VPN support (defaultRAGroup-defaultl2lGroup)

Question (short) How to set up 2 totally different dynamic l2l vpn tunnels on an ASA5506 Question (extended) We have a Cisco ASA5506 Security Appliance and we want to set up 2 dynamic VPN setups. ...
5
votes
1answer
183 views

Cisco 6500 Series and Safe Harbor Testing

It's time for our company to upgrade our Core switches (2x 6509 Sup720 in VSS). My question is if we should care about choosing a IOS image which has the certification "Safe Harbor" or not since the ...
5
votes
1answer
1k views

What is the effect of using “ntp allow mode control 0”?

I am attempting to mitigate the issues surrounding bug report CSCum44673. According to the software release notes found here, I need to ensure that all of my routers are on IOS version 15.2(2) or ...
5
votes
2answers
4k views

Changing The Stack Master of a Catalyst 3750 Without Losing Connection

Currently I have 5 Catalyst 3750 V2-48TS as slaves and 1 Catalyst 3750g 24TS-1U as the Stack Master. I was wondering if there was any way to change the Stack master to one of the slaves without ...

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