Questions tagged [cisco-ios]

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

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7 votes
2 answers
18k views

Securing Cisco device from brute force attacks

I'm trying to block users from configuring a Cisco IOS device if they have entered incorrect passwords a number of times. This is the command I'm using: Router(config)# login block-for 120 attempts 3 ...
1 vote
2 answers
10k views

RAM and ROM size on Cisco Router

I am trying to identify the size of memory available on the CISCO router. I do not have physical access to the router but I am able to login to the console and fire commands in privilege mode. I see ...
1 vote
1 answer
181 views

Monitor which SNMP communities are still in use

I am migrating from SNMP community1 to SNMP community2 on a NEXUS switch (plus a bunch of 2960s). Is there a way to monitor that the old community is not used anymore?
3 votes
1 answer
1k views

Cisco IOS Extended Access List changes destination network to 0.0.0.0

I am trying to create named extended access-lists on Cisco IOS on an 800 series router, but it changes the destination network to 0.0.0.0. Example: ip access-list extended ACL-TEST permit tcp ...
0 votes
1 answer
210 views

IOS Configure Terminal equiv in C3700 Software

I'm so used to using conf t to get into configuration mode, but it doesn't work in "Cisco IOS Software, C3700 Software (AP3G2-RCVK9W8-M), Version 15.3(3)JA3, RELEASE SOFTWARE (fc1)" What's the ...
1 vote
2 answers
1k views

Configure Log format Cisco ASA firewall

The logs from CISCO ASA fierwall is currently in the following format. %ASA-message_class-severity-messageID e.g. "%ASA-session-6-....." I want to remove messsage class from logs %ASA-...
5 votes
2 answers
335 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
1 answer
2k 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.
1 vote
1 answer
1k views

Cisco VPN Clients Routing Over IPSec VPN - ACL?

I have remote access to a Cisco 2821 Router with a security firmware license in California with an IPSec tunnel going to a site in New York. On the New York side, there is a RFC 1918 IP scheme of 10.0....
2 votes
1 answer
5k views

Cisco - #show inventory vs #show interface

I am documenting equipment which requires me to state installed Physical Layer Interface Module (PLIM)/slot and transceivers/interfaces. What confused me is the different information shown between #...
0 votes
1 answer
2k views

Change Cisco VPN User Password Question

I have telnetted into a Cisco 2851 Router with 7 set users with passwords for a PPTP VPN that show in the following format when I "show running-config": username user1 privilege 0 password 7 ...
0 votes
1 answer
443 views

IOS tools to discover a network

I would like to learn/discover a new topology. I usually use these commands. Do you know any other good tools for this? (the network have routers, switches, firewalls, multiple vrfs, vlans and all ...
0 votes
1 answer
23k views

Cisco ISR 4431 Router GigabitEthernet Flow-control Disable

I've got a new Cisco ISR 4431 Router running IOS XE 03.13.02.S and IOS 15.4(3)S2. WAN connection is a Metro Ethernet circuit delivered over copper and ISP has requested that we force the port to 1Gbps ...
5 votes
0 answers
338 views

IOS XE minimum frame size

I recently encountered an issue upgrading from an IOS device to an IOS XE ASR 1000 router concerning Ethernet Over SONET (EOS). VLAN tags are used to map traffic from the hub router to SONET ...
2 votes
1 answer
551 views

Two network routing with CISCO 878

My company uses the 192.168.10.0/24 subnet and 192.168.10.235 is for all intents and purposes the gateway to the Internet. We have an extra VDSL line with a "home-style" modem/router that we want to ...
2 votes
2 answers
226 views

Terminology on data link, channel, VLAN

I am new to networking and I'm following a CCNA course. There are a few terms that I don't (properly) understand, and I've searched for them like a mad man, but with no success. I've only read 2 ...
2 votes
1 answer
2k views

How to Block Torrents Using NBAR

I have a Cisco 1900 Series router running and I have issued whereby clients running torrents take all the bandwidth for their own use while business users suffer the damage. I tried setting up nbar ...
6 votes
1 answer
5k 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
1 answer
1k 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 ...
4 votes
1 answer
1k views

How to use secondary internet exclusively for one host?

I currently have two internet connections coming into my main office. The primary connection is regular static IP cable service and the secondary is a dedicated MPLS Ethernet connection. The primary ...
7 votes
3 answers
6k views

Edit Cisco IOS ACL without hanging the router

I have a Cisco Router 1941 Series and I want to make some changes to the access-list on the router. I got to know I will have to delete one of the list and then re-add everything again with my ...
5 votes
2 answers
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
1 answer
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 ...
4 votes
1 answer
369 views

What is the minimum interval for IOS kron?

Am I correct that minimum interval for IOS kron for reoccurring tasks is 1 minute(kron occurrence test in 1 recurring)?
0 votes
1 answer
160 views

Cisco IOS limit bandwidth to domain (wildcard) [closed]

I'm fairly new to Cisco IOS configuration. I have an 800-series router and, long story short, I'd like to limit the incoming and outgoing bandwidth allocated to some iCloud servers to prevent ...
2 votes
2 answers
1k views

How to upgrade the IOS on Cisco 2610 with 12.3

I have Cisco 2610 and it has version 12.0. I want to upgrade to 12.3 The DRAM is 32MB and Flash is 2 slots of 8MB and 8MB. Which IOS to get that fits in 8MB with 12.3?
2 votes
2 answers
7k views

Download startup config from Cisco device using SCP

I can successfully programmatically download the config from Juniper network devices using SCP - I'd like to do the same for a Cisco router. SSH access is already working, and I've enabled SCP using ...
0 votes
1 answer
747 views

Cisco 867vae not routing properly

I have got a new Cisco 867vae and connected to ADSL 2+. The connection is working well, I just dont seem to have the routing right. From the router I can Ping 8.8.8.8 but from the computer I can only ...
2 votes
1 answer
280 views

What exactly does the "show subsys" command show?

According to Cisco IOS documentation, show subsys command displays the subsystem information which doesn't tell much. Is it basically a feature list for particular IOS image similar to one in Cisco ...
4 votes
1 answer
3k views

Cisco ASA RRI and OSPF redistribution

This is a follow-up question based on this original question. The following topology is present: The Cisco ASA is our Internet firewall, as well as VPN gateway, terminating VPN connections. The ASA ...
1 vote
1 answer
3k views

How to limit the internet bandwidth to specific department in my company, using a Cisco Router?

I have this case: In my Company we have 2 Internet Access in production R1-A router and R2-B router they are both in separate networks, R2-B have the highest priority which it use to Call Center. ...
1 vote
2 answers
373 views

EIGRP active timer

Barring things like sh run | s eigrp - are there any show commands which will display the configured active timer value for a given eigrp process?
4 votes
2 answers
2k views

IOS NAT: Inside static NAT mapping one internal IP to multiple external ones

Will the following work? ip nat inside source static 1.1.1.1 2.2.2.2 route-map x ip nat inside source static 1.1.1.1 2.2.2.3 route-map x (say the remote net is 20.20.20.0 in both cases) What I'm ...
1 vote
1 answer
1k views

Cisco Catalyst 3750 switch port for VMWare ESX

We have a VMWare ESXi host with a single network port. It's connected to a Cisco Catalyst 3750 switch port and the configuration of thew switch port is as follows: interface FastEthernet 1/0/2 ...
2 votes
1 answer
287 views

Cisco IOS version

Current release: 15.0(2)SE4 Latest release: 15.2(2)SE6 ED Recommended release: 15.0(2)SE6 ED Two questions: What does the 'SE' stand for in the IOS versions? Where can I find Cisco release notes ...
4 votes
2 answers
3k views

Cisco - MtR alternatives

I trying to establish if there is a function within IOS somewhere that can provide the same results of MTR , i know it can be run from Juniper devices / *Nix & Windows devices. Goal is to ...
1 vote
2 answers
67 views

enable additional commands centrally for IOS privilege levels other than 15

Privilege level 15 in IOS has all the possible commands for particular IOS release enabled. However, for example privilege level 1 has only few dozens of commands available. Now if I want to allow ...
4 votes
1 answer
201 views

Default authentication/authorization/accounting list on all lines?

Am I correct that if one has not specified a named authentication list(login authentication ... under line configuration), authorization list(authorization .. under line configuration) or accounting ...
2 votes
1 answer
163 views

confused about cisco firewall configuration when allowing all other traffic on certain ports (src dst)

I am trying to practice some scenarios on a GNS3 lab that i am doing on my spare time (just doing a very very basic firewall for now since this is new to me) currently my scenerios I am trying to ...
6 votes
1 answer
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(...
0 votes
1 answer
3k views

how can you see what ip/mac/hostname is connected to a switch port [closed]

was wondering if there is a way for me to actually see which ip/hostname/ and/or mac address is connected to a certain port of a switch. lets say I have a 50 port switch, and a cable is going bad and/...
1 vote
1 answer
3k views

store-and-forward or cut-through switching default for cisco switches?

Finding conflicting information online. Looks like Cisco Nexus switches are cut-through by default and can be changed. Also looks like IOS switches are store-and-forward by default and some can be ...
0 votes
1 answer
536 views

OSPF Aggregation and advertisement

In My Cisco Router i configured the following OSPF interfaces: interface eth1/0 description link to net0 10.19.0.0/24 area 0 ip address 10.19.0.1 255.255.255.0 ip ospf ...
4 votes
1 answer
1k views

QoS between two sites

I have a following topology where Internet service providers for both sites provide 10Mbps connection: There is a GRE tunnel between the sites and I would like to ensure that this tunnel is up even ...
3 votes
1 answer
448 views

Securing Console Serial Ports

I am looking to secure our console ports in our remote console router equipped with HWIC-16A cards and RS232 cables. As the network admins, we usually login to these routers first (using privilege 15 ...
7 votes
1 answer
4k views

What is benefit of using CBWFQ with fair-queue statement

I mostly seeing configuration of QoS queues based on CBWFQ, witch is tripped off by shaping map. Something like below example. policy-map test class test bandwidth remaining percent 20 random-...
3 votes
2 answers
6k views

Limit bandwidth in cisco router with policy-map doesn't work

I have a problem with my scenario in limiting bandwidth of ubuntu PC in GNS3 with class-map and policy-map. this is my topology in GNS3: The R1 is a cisco 3725 router with c3725-adventerprisek9-mz....
4 votes
1 answer
5k views

load-balancing on congestion, OSPF over MPLS

I have a network of routers with two clients at both ends, as shown in the Figure below. All the routers use OSPF routing protocol over IP, and the three routers inside the "MPLS backbone" subnetwork ...
19 votes
3 answers
9k 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
2 answers
2k 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 ...

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