Questions tagged [cisco-ios]

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

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Is it possible to set maximum 32 PAT translations per global ip address?

So basically I'm trying to configure a cisco router (c7200) to use PAT with a pool of global addresses, and each global address should only support a maximum of 32 private addresses. I've been ...
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0 answers
31 views

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 ...
0 votes
1 answer
20 views

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 ...
0 votes
1 answer
506 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 votes
0 answers
109 views

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: ...
1 vote
1 answer
149 views

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 ...
0 votes
1 answer
63 views

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 ...
1 vote
2 answers
67 views

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 ...
0 votes
1 answer
55 views

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?
5 votes
2 answers
22k views

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 ...
0 votes
1 answer
81 views

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 ...
5 votes
2 answers
1k views

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 ...
0 votes
1 answer
192 views

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 ...
1 vote
1 answer
122 views

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?
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38 views

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 ...
0 votes
2 answers
204 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 ?
2 votes
0 answers
111 views

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 ...
1 vote
2 answers
2k views

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 votes
1 answer
72 views

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 ...
4 votes
2 answers
6k views

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 ...
0 votes
1 answer
622 views

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 ...
1 vote
1 answer
56 views

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 ...
3 votes
1 answer
82 views

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 ...
3 votes
1 answer
923 views

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?
4 votes
3 answers
245 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 ...
0 votes
0 answers
43 views

No Adjacency-SID label in packets in SR topology

I configured Segment-Routing on Cisco IOS XE 17.03.3 in lab environment. You can see topology in the attachment. I configured IS-IS as IGP protocol. It also advertise SR labels. Global-SID static ...
0 votes
1 answer
41 views

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 &...
1 vote
0 answers
51 views

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 ...
2 votes
1 answer
124 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&...
1 vote
2 answers
151 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, ...
4 votes
3 answers
2k views

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
125 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 ...
5 votes
4 answers
40k 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....
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45 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 ...
2 votes
1 answer
233 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 ...
0 votes
0 answers
84 views

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

I glad for any help on this topic -- netanel
0 votes
2 answers
64 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 ...
0 votes
0 answers
361 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
4 votes
2 answers
5k views

I can't set a gateway of last resort

I can't seem to get to set a gateway of last resort on a router. I want it to forward anything whom's ip address is not in the routing table to router HQ through interface s0/0/0 by doing the ...
0 votes
1 answer
321 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 - ...
0 votes
1 answer
63 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?
1 vote
1 answer
95 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 ...
0 votes
0 answers
76 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 ...
0 votes
0 answers
344 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/...
0 votes
1 answer
72 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 ...
2 votes
2 answers
164 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 ...
8 votes
5 answers
59k views

Switchport mode access VLAN & switchport mode trunk on one interface

Googling around to see if this setup on one port is correct (it doesn't look right to me), I'm not really seeing a straightforward answer. There is an interface with the following configuration: ! ...
1 vote
0 answers
312 views

Amazon AWS VPN Bidirectional Device Access

After setting up an Amazon VPN connection and configuring my gateway using the downloaded configuration, I am able to directly ssh to the private IP of an EC2 instance in my VPC. However, both the EC2 ...
3 votes
1 answer
2k views

Cisco ipsec tunnel with nat to aws customer gateway

I'm trying to configure an IPSec tunnel between a Cisco router (ISR) and AWS (Customer Gateway). The connection to the ISP here is a PPPoE connection with a static private IP (e.g. 10.100.1.1) which ...
0 votes
1 answer
56 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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