Questions tagged [cisco-ios]
For discussion about Cisco's Internetwork Operating System - Cisco IOS
575
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11
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Fast port connection and ability to daisy chain unmanaged switches on Cisco Catalyst [duplicate]
I have a Cisco Catalyst 2960-S that I use in a home environment.
In the configuration I currently have (very basic, basically just switchport mode trunk on upstream and switchport mode access on reset ...
- 101
3
votes
1
answer
313
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Cisco ISR Zone Based Firewall dual stack not matching returning traffic for ipv6
I have a bit of a problem with my Cisco 1921 ISR config. I have ipv4 (obviously) and also native ipv6 connectivity in my home lab. I am trying to set up the zone based firewall. With ipv4 traffic, the ...
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5
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4
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41k
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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....
1
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0
answers
24
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Set promiscuous port for upstream LACP trunk on Cisco 2960X
I have a series of clients who are looking into a intra-VLAN isolation scheme to satisfy a DDQ request.
I was looking into deploying private VLANs for all client device / voice VLANs to satisfy this ...
- 11
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1
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23
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Unable to configure Site to Site VPN between Cisco Router & Cisco ASA and permit SSH
I am performing configuration on Cisco ASA and Cisco Router from the packet tracer. I am attempting to allow the external network (172.16.22.100 255.255.255.0) to access the internal server which is ...
- 2,070
1
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1
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172
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Cisco port channel identification through SNMP
on a cisco switch is there any way to identify, through SNMP queries, which interfaces are involved and configured in a port channel?
I did some experiment with commons MIB, without result.
Any idea?
...
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0
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42
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Using ACR (adaptive clock recovery) across pseudowire
I am using back to back Cisco 2941s (mwr2941-adviprank9-mz.151-3.MRA3) in the lab to attempt to establish a pseudowire circuit for T1 delivery. I am trying to establish timing by using adaptive clock ...
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27
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Cisco switch ios update without change license
I need the following ios switches to be updated to the latest "license-free" version to fix vulnerabilities:
C3560CX-12pd-S
C3650-48PS-E
C3850-12S-E
C3850-24T-E
C3850-12S
I didn't find any ...
3
votes
4
answers
223
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where does the running-config come from in a new fresh switch?
Generally, in a fresh switch, I see a startup-configuration.
Switch#show startup-config
startup-config is not present
But when I do 'sh run' I see a default running config in it. Where does this ...
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9
votes
2
answers
2k
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How to break apart an IPv6 /56 6rd delegated prefix from ISP into multiple /64 VLANs for use with SLAAC EUI-64? [Cisco]
I have CenturyLink Internet service, and they have a 6RD IPv6 deployment where they hand out an IPv6 delegated prefix /56 block to me and allow me to use it as I wish. My Cisco ISR router receives the ...
0
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1
answer
233
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Issue w/ Cisco router and failed NAT and static default route
I have a cisco router that is using a VRF to support a site to site VPN tunnel. I have added a second network to the router for non-VPN standard internet use. My problem is that my default static ...
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0
votes
1
answer
515
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Prioritizing SSH, Telnet, TACACS in Cisco IOS
For Prioritizing SSH, Telnet, TACACS locally generated traffic on Cisco ASR running IOS XR, we have:
ssh server dscp 48
tacacs-server ipv4 dscp 48
Need the same for cisco GSR: 12416/PRP running IOS. ...
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1
answer
27
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Does this DHCP Server need a trusted ARP Inspection port in IOS?
The switch runs Cisco IOS. You want to configure security on Switch 1. The objective is configuring Dynamic ARP Inspection on Switch 1. Which Ports or port will you configure as Trusted?
A) None of ...
- 82.8k
0
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1
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97
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Will an OSPF route in IOS be preferred over a static route? (It isn't Floating Static)
For the network topology attached in the image, a static route is configured with ip route 10.10.10.0 255.255.255.252 Ethernet0/0. Referring to the Topology and the output from the show ip route ...
- 31.8k
2
votes
2
answers
100
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Cisco IOS - how can I make the guestshell be reachable via VRF?
I am currently trying to set up a cloud application on the guestshell of an ISR4331. It installs a connector that needs to have connectivity to the internet. I assume the issue is not specific to what ...
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1
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1
answer
69
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Cisco 4500x configure fast-hello interface with multiple ports
I have a pair of cisco 4500x-32 and i configured VSS between then but i am using just 1x 10G interface for fast-hello packet and here is that interface configuration:
interface TenGigabitEthernet1/1/2
...
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2
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2
answers
226
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How to ensure startup-config is not changed, building CCIE rack
Let me start with short background for better understanding.
We have LAB at work (Cisco devices mostly), and we would like to allow other employers connect remotely from their homes, build own labs ...
0
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1
answer
587
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Configure NCS540 IOS XR router works as Layer 2 switch
I have an NCS 540 Router and would like to config it as an L2 Switch. In the diagram, PC2 and PC3 should get the IP addresses from pfSense(DHCP and DNS). How can I setup the trunk port for the NCS540 ...
- 2,070
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0
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28
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Cisco Firewall 5512 NAT cause IP randomly mapping to the host
I have an ASA 5512 firewall that has configured with 2 public IP addresses.
I use static nat to explosive https service and use PAT to allow my DMZ web server to access the Internet. The CLI are shown ...
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0
votes
1
answer
806
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Dual WAN with each ISP in a VRF - Cisco IOS
I have a DMVPN spoke router setup almost identically to the spoke configuration listed here (Also quoted below):
https://www.cisco.com/c/en/us/support/docs/security-vpn/dynamic-multi-point-vpn-dmvpn/...
CommunityBot
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52
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Is there a password policy configuration for setting up expiration date on cisco IOS?
Even I tried to find it from cisco homepage..
It seems it doesn't exist.
Is that only possible to set up on TACACS+ or RADIUS?
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156
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Show on a Cisco 3850 Switch if a new IOS is installed
We have some Cisco 3850 that we never get downtime to do software upgrades (current uptime of switches is over 4 years). Tomorrow there is power works in the room so these switches will lose power so ...
- 2,638
0
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1
answer
73
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GNS3 Router Telnet Configuration
I configured the IP address and telnet for my Cisco router but on GNS3 it shows a different IP address. When I ping the router from my Ubuntu virtual machine using the IP address I configured the ping ...
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2
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0
answers
239
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Problem with BGP aggregate-address behavior in IOS when a large number of OSPF routes update all at once
We have a Direct Connect setup to AWS using BGP. We are running a ISR4451 with IOS XE 16.03.06.
I have a strange situation where the AWS BGP neighbor drops our connection with the notification: ...
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1
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1
answer
325
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how to limit or block broadcast traffic on ASR920 service instance EVC
I don't want to turn off all port,
I want to block completly broadcast traffic,
or the best to limit rate to 500 pps broadcast, all more to drop.
Is there any way to do it on Cisco ASR920?
I have ...
CommunityBot
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0
votes
1
answer
275
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Naming ASN something else than "default", Cisco IOS XR
I'm trying to configure a BGP and VRF (for a L3VPN) on a Cisco ASR9000 router, as per this tutorial.
I'm on the first section ("Configuring Multiprotocol BGP on the PE Routers and Route ...
CommunityBot
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1
vote
2
answers
233
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What interfaces does a Cisco iOS Router allow SSH Console access on?
I am have trouble understanding how Cisco iOS maps console access services like SSH to IP addresses.
Assume the following:
There are no acls blocking traffic
There is the typical SSH server ...
- 135
0
votes
1
answer
192
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How to change the AS number without losing the old BGP configuration?
I use Cisco with IOSv and would like to change AS number without losing the old BGP configuration.How to change the AS number without losing the old BGP configuration?
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5
votes
2
answers
22k
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SNMP: Configuring/Enabling SNMPv3 on Cisco IOS and SNMP Agent
I have been configuring and using SNMP v2c on Cisco routers.
Due to the obvious advantages in SNMP v3, I am planning on enabling SNMP v3 on SNMP v3 supported devices.
Could someone let me know:
The ...
CommunityBot
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0
votes
1
answer
327
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What could be blocking ARP?
I have a metro ethernet link between two offices with Cisco C3560X's on each end. Actually, I have two links. (We are switching from one provider to another.)
I can't get the new link to work. Pinging ...
- 464
5
votes
2
answers
1k
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Enable SNMP traps for ACLs using Cisco IOS?
Does anyone know if it's possible to enable SNMP traps to be sent from a Cisco IOS device when an ACL blocks traffic? I'd like to send a trap whenever a deny statement gets a hit.
I've only been ...
CommunityBot
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1
vote
1
answer
157
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implementing broadcast traffic restriction
Can we restrict the high broadcast traffic from interface in Cisco ASR9k and 7600 routers? If so, what configuration we should apply?
CommunityBot
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0
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93
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Admin IOU L3 switch
Problem with IOU l2 switch
By Konstantinos Dimos
July 31, 2022 at 3:12 UTC
Hi, under Ubuntu 22.04 LTS, gns3 and local server I am trying to manage switch IOU L3 switch, although at the begining I was ...
- 82.8k
0
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2
answers
296
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Steps for upgrading to Cisco DNA Center?
Has Anyone upgraded from cisco Prime to Cisco DNAC, if so then Does anyone have Steps (Prep Work) checklist suggestions before beginning the Brownfield Deployment of Cisco DNAC ?
CommunityBot
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2
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0
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343
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Cisco Access Switches: Monitoring AAA server dead via SNMP?
This is a new setup of Cisco access switches (2960S, 2960X IOS with 15.2(2)E9, but mostly C1000 with IOS 15.2(7)E*), with a Cisco ISE 3.0 as authentication server for 802.1X, config style is to be ...
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2
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2k
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Cisco IOS Version changes for SNMPv3 server-group context
I'm trying to understand switch mapping using SNMPv3. It's come to my attention that the group(user) who is authenticating needs access to thecontext
for mapping out VLANs. I've figures out this can ...
0
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1
answer
151
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BGP Protocol configuration between two VPC
I would need to configure a cross connect between two VPC networks via SFP Fiber. Unfortunately I'm new on BGP configuration and would need confirmation that I'm doing it on the right way...
I have ...
- 103
4
votes
2
answers
7k
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Is there a way to copy via SCP from the switch/router but specify the remote port?
According to IOS documentation*, you can initialize an SSH session from a switch/router and indicate the remote port to connect to, ex. ssh -p 22222 1.1.1.1
SCP, however, doesn't seem to have that ...
- 348
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1
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2k
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Cisco ASR 1001 transceivers not working
I've a Cisco ASR 1001 v03.
When it got to my hands it wouldn't save the config after reboots, after some research I found out the config-register had a wrong value and it was fixed by running ...
CommunityBot
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1
vote
1
answer
105
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Cisco 4500X TCAM question on PBR
I have a pair of 4500x in VSS mode and i have 100-150x SVIs and i have PBR under those SVIs and i am changing their next-hop, i want to know PBR and changing next-hop happens in TCAM, hardware or it ...
CommunityBot
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3
votes
1
answer
323
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Cisco 9400-Supervisor Engine 1XL uplink help
I have inherited a Cisco 9400 with 6 line cards installed. I am trying to use some ports on one of the cards. I noticed that there is no link activity lights, no indication of any activity.
I think ...
- 98.8k
3
votes
1
answer
1k
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Filtering IP packets that contain IP options using ACL
Is it smart to have ACE
#deny ip any any option any-options
enabled as part of hardening the router?
Is there some legitimate traffic that use IP options? Or should I use selective drop?
- 29.9k
4
votes
3
answers
291
views
IOS Memory allocation error after ping
I have written a script in Tera Term for a Cisco IR809g which pings 3 different routers(IR 809g) in 2 different networks over the cellular interface. After +- 6 hours I'm getting a Memory allocation ...
- 82.8k
0
votes
1
answer
69
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Cisco ACL Entries
I have a cisco 4500x and n5k-5672up and in their datasheet mentioned that we can have "Security ACL Entries (1K=1024) 128K (64K ingress and 64K in egress) Shared with QoS" for 4500x and &...
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0
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83
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TACACS Through ASA L2L Tunnel
Hello see below network diagram.
I am trying to configure the Branch Router (10.1.1.1) to use TACACS AAA on the HQ-AAA-Server host (192.168.10.10). TACACS works fine for the Branch-FW1 ASA device ...
- 171
2
votes
1
answer
269
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AAA Authorization on IOS
Still working away on a project (not for real life deployment so don't worry about seeing passwords).
I have a Tacacs server set up for centralised AAA. I am trying to set up two users, "admin&...
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1
vote
2
answers
412
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events log in cisco
Is there log file just like events file in windows showing what happened,who did what, kind of ? I could not see with show archive log.some switch goes down and support guys plug off/on cisco switch, ...
- 82.8k
4
votes
3
answers
3k
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DHCP Server Port-Based Address Allocation on Cisco switch 2960-x
I am trying to configure DHCP Server on a Cisco 2960-X switch to achieve port-based address allocation. I would like the IP address assigned to any device connected to that port to be the same every ...
1
vote
0
answers
384
views
Route-map to manipulate metric in EIGRP
I have following Setup
R1 --- R2 --- R3 --- R4 --- R5
The same network is being advertised from R1 and R5. There is some difference in delay between the two paths R1-R2 and R4-R5. So the route from R1 ...
- 1,700
0
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0
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79
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Update IOS on Cisco CGS2520 Switch
I need to update the IOS on a Cisco CGS2520 Switch. Not stacked, single switch
I have never done this before and I have a couple questions.
I do not have physical access to the switch.
Looking at the ...
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