Questions tagged [cisco-ios]

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

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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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1answer
83 views

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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9 views

doubts ethernet NIC [closed]

I have a question, it may be stupid but I have that doubt I have an ethernet card for fiber optics, if my ethernet card is 1 gb / s I think that is the bandwidth of the interface and my fiber optic is ...
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26 views

OSPF peering is not forming and is looping through the states [closed]

Any ideas or hints on what could cause an OSPF peering to break and start looping through states indefinitely? The adjacency is formed with no issues after a reboot (of the other peer) and remains ...
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2answers
34 views

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, ...
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32 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 ...
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2answers
167 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 ...
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27 views

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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29 views

How do I load VLAN database between switches (CISCO 2960)?

I glad for any help on this topic -- netanel
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2answers
56 views

Client's ARP requests affect whether Cisco C897VA receives packages or not

So I have bought used ISR C897VA with an issue: when vlan1 is pinged from windows there are quite a lot of "Request timed out"s. Config-register 0x2142 has been done, as well as resetting ...
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66 views

No Voice commands on cisco router

I cannot find voice commands on my router, I have licenced it but no voice commands or sip are found Its on packet tracer. Cisco router 2911 Thank you
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1answer
80 views

Addresses in router's subinterfaces overlapping [duplicate]

I can't really understand why I'm getting overlapping addresses in subnets when they're between the allowed range. I have the network 192.168.1.0/24, and I have to create 3 subnets: A - 58 Hosts B - ...
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1answer
59 views

How to query which line I am configuring in a Cisco router?

The Cisco router prompt shows only that I am configuring a line: config-line. How can I make IOS to print exactly which line I am configuring?
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1answer
39 views

ARP sending an ARP request on changing port IP address

Using the c7200 images on GNS3. I configured two routers as so: With arp debugging on, after assigning an ip address I see that each router sends a gratuitous ARP response packet (only debug output ...
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30 views

Cisco firewall Firepower 1120 how to access global configuration mode?

Cisco firewall Firepower 1120 how to access global configuration mode? Commands enable and configure terminal are not working.
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38 views

Cisco DHCP using dynamic updates

I would like to use a configuration on a Cisco router that allows for clients to resolve the names of other clients without the use of mDNS. I have following configuration: roTST01#show running-config ...
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92 views

Can ping from VPC 1 to router and VPC2, but can't ping from switch to VPC2 or router

I have a simple, linear topology in GNS3 that goes like this. VPC1 > Switch > Router > VPC2 I have the default static IP Routes on the router set to 0.0.0.0 0.0.0.0 Ethernet0/1 and Ethernet1/...
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1answer
34 views

How to stop automatic entry as privileged exec from console login?

I am configuring my Cisco router and trying to set up access levels. I was under the impression that level 0 was a very limited mode which almost only allows users to enter the enable command to enter ...
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2answers
71 views

Unable to add an abbreviated IPv6 to a Cisco router

I am very new to networking and playing around with GNS3. I am trying to configure a router to have 2 IPv6 addresses in a single interface (as far as I understood, this is possible with IPv6) I ...
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1answer
29 views

IP Source Guard On Static Networks

I am running a set of Cisco C9300s. I have them configured with ip dhcp snooping, and ip arp inspection with ip dhcp snooping trust and ip arp inspection trust set on the fiber link between the 2 ...
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1answer
34 views

In France , what language is the Cisco IOS for routers and switches?

If I accept a Network Engineer job in France, what language will the Cisco , Juniper, etc, IOS communicate in? If it is in French, is there an acceptable workaround that I can install in routers that ...
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1answer
38 views

Why does a Cisco router advertise a prefix with NDP RA when it has an address in that range?

If I write interface Vlan1 ... {ipv4 config} ... ipv6 address 2001:DB8:5432:101::/64 eui-64 ipv6 address FDAA:DB8:5432:101::/64 eui-64 ipv6 enable ipv6 nd prefix 2001:DB8:5432:101::/64 ipv6 nd ...
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57 views

show ip nbar port-map is deprecated

If I want to see what parameters NBAR uses to classify traffic into a specific application, i used to use show ip nbar port-map. It was looking something like this: Router# show ip nbar port-map dhcp ...
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1answer
131 views

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 ?
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1answer
238 views

Cisco ACL numbering

This is a small technical question. I can't seem to find any information on this, so I thought I'd ask here. I'm currently studying for my CCNA and I'm currently on the topic of ACLs. On IOS standard ...
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1answer
344 views

4500x ios upgrade

I have a Cisco 4500x-32SFP (with Enterprise License) with cat4500e-universalk9.SPA.03.04.04.SG.151-2.SG4.bin ios and i want to upgrade it to cat4500e-universal.SPA.03.11.03a.E.152-7.E3a.bin which is ...
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1answer
141 views

Cisco ip helper-address

I am looking at the DHCP documentation and i cannot seam to find how to configure the router to use a loopback interface as the relay-agent. My objective is to use option 82 so that the dhcp server is ...
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1answer
21 views

Multiple administrator connecting to a router - who has precedence? Can they monitor each other's logs?

Just getting started in Networking. Came across multiple administrators connecting over Telnet. Does someone who connected first have precedence over everyone else? Does a admin connected to VTY line ...
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3answers
3k views

How to remove switchport mode access from Cisco Switch 2960?

This is in Cisco Packet Tracer - this is not a real switch. Default interface config on Cisco Switch 2960 looks like this ! interface FastEthernet0/10 ! Then I put it in switchport mode access ! ...
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1answer
321 views

IP SLA VS tracking IP-route reachability for HSRP

I have two Cisco switches A and B, which I want to use HSRP to track if route to specific IP still works, but according to my understand it could be either IP SLA or tracking IP-Route Reachability ...
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1answer
121 views

IPCP removing default route when 2 available

I've been stuck on this one in my lab for a while. Any help is appreciated. Here's my CPE edge topology: https://i.imgur.com/UZ4u0XG.png Take the below scenario: I have 2 circuits coming in that I am ...
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2answers
2k views

Why does the CISCO's command 'enable secret <password>' produce different hash from MD5?

I am configuring a CISCO's 4331 router password, in Packet Tracer. More specifically I use the command enable secret weakpassword. This command uses by default MD5 to hash the last string (i.e ...
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2answers
772 views

Safe to remove ip default-gateway?

We recently changed IP schemes from 192.168.x.x to 10.x.x.x In doing so, I noticed that the prior network engineer had ip default-gateway in the configuration pointing to an old default gateway that ...
2
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1answer
38 views

Cisco router with 3 spaces between `deny` and `icmp`

I was configuring deny icmp any any traffic when I realized it was not in the config. I verified it with do sh run | i deny icmp command as follows: R1#configure terminal Enter configuration commands,...
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1answer
44 views

Cisco IOS How to dynamically change the queueing/shaping upload bandwidth for xDSL circuits?

In Cisco 29xx routers with IOS 15.7, we have upload queues (with the classic service-policy output command and the policy-map: policy-map wan-shaping class class-default shape average 1024000 ...
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2answers
82 views

Add allowed vlan to vlan.dat automatically

I have a switch configuration for a Cisco 2960cx that allows a specific VLAN on a trunk but no interface on the switch explicitly accesses that VLAN. So when the configuration is ran for the first ...
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0answers
309 views

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/...
2
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1answer
147 views

SNMPv3 context on IOS-XE does not seem to work with Prime

We recently switched to SNMPV3 and experience the issue, that there is no client data available within prime anymore. So we quickly read about the SNMP context we need to add to our devices ...
2
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1answer
58 views

Routing failed after define static route on core switch

Current connection path: 10.40.20.0/24 desktop <-> access switch <-> core switch <-> 10.30.15.33 NAT firewall for internet access Objective: adding additional path as following to ...
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2answers
62 views

How can I auto-detect the default WAN gateway on a Cisco router?

I previously connected to my ISP using authenticated PPPoE and provided default routes for IPv4 and IPv6 as follows: ip route 0.0.0.0 0.0.0.0 Dialer0 ipv6 route ::/0 Dialer0 After switching to a ...
1
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1answer
794 views

Force Catalyst 2960X Boot Loader upgrade to the same version

I would like to know if there's a way to force a Boot Loader rewrite on Cisco Catalyst 2960-X switches. I got one model that runs this release of the Boot Loader: BOOTLDR: C2960X Boot Loader (C2960X-...
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2answers
69 views

Why we define pool for declaring CISCO router DHCP?

In case declaring DHCP server in CISCO routers, should define pool with network addresses.↓ Example Router(config)#ip dhcp pool net1 Router(dhcp-config)#network 192.168.1.0 255.255.255.0 The router ...
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1answer
45 views

Routing between two sites using FTTC Broadband and E-Band Wireless

I have two sites, both with 80/20 FTTC broadband connections that terminate at the standard white box BT modem. The connections both have fixed IP. I’d like to connect these up to each other and form ...
0
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1answer
79 views

What is the purpose of Cisco's `ip domain round-robin` feature?

While configuring one of Cisco's routers and reading documentation I've found an interesting feature: ip domain round-robin. Documentation says, that this options makes dns server rotate entries ...
0
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1answer
128 views

How to init connection with a Cisco over serial & minicom?

Trying to connect to a Cisco router, in purpose to learn Cisco skills that could help me finding a job. So, I plugged a cable in the rj45 Console (blue) port of a Cisco 888 router, and other end into ...
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3answers
55 views

Show ports in use on Catalyst 3570

I picked up a used C3570 and am new to IOS. I am trying to ask the switch to show which ports are in use. My searches lead to the command "show modules" but that's refused by the switch (...
1
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1answer
118 views

QoS Policy to not overutilize WAN link

I have a configuration on a Cisco C897VA-K9 router that has a built in DSL modem. It has a simple internet connection via VDSL. There is a VPN configured on the device, that connects back to our main ...
0
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1answer
26 views

Traffic flow of tunnel interfaces

I would like to understand traffic flow in a router. In what direction do i need to apply a policy-map in order to affect traffic? Especially regading tunnel interfaces, as traffic both comes and goes ...
3
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1answer
596 views

Cisco IOS NTP do not sync time after reboot

I try to setup automatic syncing time on Cisco Catalyst 2960-CG-8TC-L switch using following command. ntp server 0.cz.pool.ntp.org and it works and sync time but after switch reload it does not sync ...
3
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2answers
106 views

Understanding traffic flow on SVIs [closed]

I have a simliar question to this one: Access-Lists and VLAN and understanding traffic flow But my question is concerning service-policies. Have a look at the image above. I triet to make a traffic ...

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