Questions tagged [cisco-ios]

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

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2 votes
1 answer
280 views

Cisco Embedded Packet Capture with NAT

I love the ability Cisco's Embedded Packet Capture (EPC) provides to remotely troubleshoot dataflows on IOS routers. monitor capture buffer CAP_BUF monitor capture point ip cef CAP_PT gig 0/0.1 both ...
4 votes
2 answers
372 views

PAT not translating at all

I am studying for my CCENT. I threw together a PAT practice lab. Other than DHCP and RIP everything is pretty stock. No VLANs No security Just NAT overload on ACCESS router. I am stumped why it isn'...
5 votes
2 answers
212 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 ...
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1 vote
2 answers
4k views

How can I ping with source option in Cisco Router?

How can I ping with source option in Cisco Router? I have a ISR 4321 Router, I want to ping from a source IP address: Router#ping ? WORD Ping destination address or hostname ip IP echo ...
1 vote
1 answer
320 views

Help with small office setup - Cisco SG350 28 port switch

I have very limited knowledge in Cisco IOS but in a crucial state to setup up a small office network. I have bought 2 Cisco SG350 28 port Layer 3 switch, Switches should be enabled with VLAN and VTP. ...
3 votes
1 answer
319 views

Set password of a Switch to "C?1sc0" using CLI in Cisco Packet Tracer

I have been asked to set the password of a Switch to "C?1sc0" in Cisco Packet Tracer. The problem is that when i type "?" in CLI it prints out: Router(config)#enable password ? 7 Specifies a ...
1 vote
1 answer
350 views

DSCP re-marking on Cisco Switch

I've followed the commands in this post: DSCP trust boundary policy-map MARKDOWN class class-default set dscp ef Interface Config: interface gig 0/1 service-policy input MARKDOWN The ...
1 vote
1 answer
388 views

How to run SIP phones in the LAN (NAT Overloaded to single IP)?

We have a small office network switch connected to a DSL modem for internet and telephony access. Now we would to extend network to another location in the same building for which I deployed a cisco ...
  • 113
4 votes
2 answers
794 views

After I set the "router rip" networks, how can I check it?

In my CGR1240 I have set network 192.168.1.0 to my router rip, but how can I check it? If I add more networks in rip, how can I list all the networks I have added? I can not show the router rip in ...
4 votes
2 answers
1k views

Why the Cisco Router's loopback interface can not be showed up by default?

By default, why the Cisco Router's loopback interface can not be showed up? Router#show ip interface brief Interface IP-Address OK? Method Status Protocol ...
  • 1,737
1 vote
3 answers
68 views

Is the static route discover automatically or need run any command in Cisco Router?

Is the static route discover automatically or need run any command? I have two router, and I have configured the IP address for the link port of them. but the Router3's route is empty: Router#show ...
  • 1,737
4 votes
2 answers
2k views

Cisco Router GigabitEthernet interface can not add ip address?

Cisco Router GigabitEthernet interface can not add ip address? Router(config)#interface gigabitEthernet 2/1 Router(config-if)#ip add ? % Unrecognized command Router(config-if)#ip add 12.12.12.1 255....
  • 1,737
2 votes
1 answer
6k views

How to configure DHCP pools for 2 VLANs/subnets sharing a switch

I've set up DHCP pools on a layer 3 switch that goes out to 13 layer 2 switches. Most of which have their own subnet and VLANs, and everything works fine when that's the case. But when there are two ...
  • 293
1 vote
2 answers
88 views

Is it possible to enable DHCP on multiple hosts via Cisco switches or routers? [closed]

I think I know the answer to this, but thought I ought to ask around. When setting up new networks with multiple hosts, like a university computer lab VLAN with 30+ workstations, for instance, is it ...
  • 293
2 votes
3 answers
3k views

Virtual Appliance - Cisco Router

My colleague said that it is possible to virtualize a Cisco router i.e. run the Cisco IOS inside ESXi and it would act like a real cisco router so thus can be used in a light production environment. ...
4 votes
1 answer
170 views

CISCO IOS's feature Secure Shell Version 2 Enhancements for RSA Keys

I have a switch C3750V2-48PS with IOS ver. 12.2(55)SE5. I wanted to copy to it public key for the ssh client but I do not have following command available Switch#configure terminal Switch(config)#ip ...
  • 177
0 votes
1 answer
64 views

Cisco IOS 12.3 - Mysterious NAT - Where is it defined?

I have the following config (IOS 12.3): A.B.C.13 stands for the outside, public IP, bound on interface Fa0/1.52 37.247.X.206 is a public client I am using to test x.x.x.n stands for a random public ...
  • 1
1 vote
1 answer
82 views

Access list per port for 48-port switches

We have 3750g, 3750e, 4948, 2960 series Cisco switches and all of them are 48 ports so we want to create one standard access list per port switch and in every ACL we permit 5-6 prefix (short prefixes ...
1 vote
3 answers
1k views

Cannot put an IP address on layer two interface

I am trying to assign an IP address to Interface g0/0 on a Cisco 892FSP. However, it keeps telling me that a layer two interface cannot be assigned an IP address. Any ideas?
3 votes
1 answer
66 views

what is the point of making directories in a cisco cli

what is the point of making directories in a Cisco router. I noticed its was kinda like Linux mkdir and all that stuff, but what is the purpose?
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2 votes
1 answer
1k views

Assign DHCP IP address on Cisco router interface

Hi, dhcp router is configured with following DHCP settings: ip dhcp pool B network 192.168.1.0 255.255.255.0 default-router 192.168.1.1 ip dhcp pool C network 192.168.2.0 255.255.255.0 default-...
  • 177
1 vote
1 answer
18k views

how to deny ping from one direction but not the other using Access-list

Hello everyone. What I'm trying to do is to deny ping access from the 12.12.12.0 network to reach the 10.10.10.0 network but not deny ping access to go from 10.10.10.0 network and reach the 12.12.12....
4 votes
2 answers
85 views

Routing Table Eligibility

I have an architecture which is that each remote site has 2 Dialer interfaces dialling into a virtual-template core which authenticates the sessions and applies attributes from a RADIUS server. OSPF ...
3 votes
1 answer
701 views

How to get per-process memory use from Cisco switches via SNMP

I'm trying to get per-process memory use from Cisco switches via SNMP. I've found an article suggesting you can subtract CISCO-PROCESS-MIB.cpmProcExtMemAllocatedRev and CISCO-PROCESS-MIB....
1 vote
1 answer
89 views

Cisco 4948 can ping out, but no connections inboud

n00b question here I suspect... I received a used Cisco 4948 (not an 'E' or 'F') Switch that I am trying to get configured for SSH Management access. I can ping out from the switch to nodes that are ...
5 votes
1 answer
557 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 ...
  • 1,016
0 votes
1 answer
2k views

Cisco ios - loading 15.2 into Catalyst 2960

Is it possible to load cisco ios 15.x into an old 2960 or 3560? I tried to do that (study purpose) and it's throwing an error. The error I see apparently has to do while decompressing the image or at ...
1 vote
2 answers
958 views

Configuring static NAT on Cisco Router

I am trying to configure port forwarding on a Cisco 891F router given by an ISP and directly connected to servers in the 192.168.170.0/24 network. The ISP recommended using the ip nat inside source ...
  • 280
2 votes
1 answer
2k views

cisco 3750x switch boot loop after failed IOS software upgrade

I was trying to upgrade WS-C3750X-48T-S IOS software from universalk9-mz.122-53.SE2.bin to c3750e-universalk9-mz.152-4.E6.bin First I deleted all files under flash: folder, then downloaded new one ...
  • 147
1 vote
1 answer
41 views

Subinterfaces at Cisco routers

What is behavior of subinterface on cisco router that has configured #encapsulation dot1q vlan_id but has no IP address configured? Will it work as L2 interface? Or will not work at all?
  • 812
1 vote
1 answer
128 views

Can cisco router interfaces be configured to be L2 interfaces?

Can cisco router interfaces be configured to be L2 interfaces? Like #no switchport command turns L2 port to L3 port at cisco switches?
  • 812
1 vote
1 answer
4k views

Factory Reset Cisco 3560: Stuck in loop

I recently acquired a used Cisco Catalyst 3560 and I am trying to factory reset it. When I enter the recovery process (by holding MODE), I get stuck in this loop at the "switch: " prompt. How do I ...
3 votes
1 answer
1k views

Fix our Cisco switch overwhelmed by console logging

I have a setup with dual redundant Cisco catalyst 4506-E using the WS-X45-SUP8L-E supervisor engine and two 48-port switches below it. My task is to access and modify the switch configuration. ...
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?
  • 812
1 vote
1 answer
51 views

Help with this acl

This is what i am trying to do Deny the network that host 200.200.200.10 is on, telnet access to R3 Permit host 200.200.200.10 to telnet to R3 Deny host 200.200.200.10 all access to host 204.10 on ...
8 votes
3 answers
1k views

routing between vlans not working

I need to put a Cisco router behind an ISP router. (The ISP doesn't allow us to use their modem only.) I've called the ISP technical service and they've set up the connection with me. Their router ...
  • 213
5 votes
1 answer
497 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 ...
  • 812
1 vote
1 answer
119 views

Using a Cisco router to create a network inside an existing one

I have to make the 192.168.1.* network inside the already existing 192.168.0.* network using a Cisco 2821 router. I'm not familiar with Cisco IOS, and I have no idea what commands to use and how to ...
5 votes
2 answers
231 views

Automation out of the box?

Can anyone point me in the right direction ? I have been recently learning python with the goal of learning more about network automation, I can copy, paste, tweak and adjust a simple script to ...
5 votes
2 answers
1k 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 ...
8 votes
1 answer
1k views

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 ...
2 votes
1 answer
377 views

DHCP Relay Problem

I'm trying to get DHCP to work between these two Devices. Any tip's would be wonderful! Switch Config Switch#show run Building configuration... Current configuration : 1596 bytes ! ! Last ...
5 votes
1 answer
4k 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 ...
  • 1,713
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 ...
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5 votes
3 answers
5k 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 ...
1 vote
2 answers
971 views

IPSec VTI on Cisco ISR reporting up/up and decapsulating packets, but not encapsulating

I'm configuring a VPN connection between two sites. Site A has an ASA (9.8.2) and the other site an ISR 2911 (15.4 I think - I'll have to double check). I'm using VTIs for a routed VPN. The tunnel is ...
3 votes
2 answers
5k views

Editing startup-config

I have a Cisco router, and I want to remove a few lines from startup-config. How could I do it? Do I need to copy it over to a PC, edit it there, then copy it back, or can I do it through the serial ...
3 votes
1 answer
475 views

CSCvg76186 - Cisco Smart Install Remote Code Execution and Denial of Service Vulnerability

If you missed this Catastrophic severity 1 vulnerability, check the temporary solution below, if you do not want to upgrade your software to a not properly tested software. There are currently, at the ...
user avatar
3 votes
2 answers
278 views

Converting a Cisco 827 for FTTN NBN

I have a customer who is moving to NBN in a few months and I thought I would start to look at the config changes now when there is no time pressure. I assume I will have 2 options: Change the ...
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2 votes
3 answers
1k views

Translate between multicast addresses

I have an application with a bug that does not recognize a certain multicast address as valid. It's an address used by another system i don't have control over, and these two systems communicate via ...

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