Questions tagged [cisco-ios]
For discussion about Cisco's Internetwork Operating System - Cisco IOS
528
questions
0
votes
1answer
25 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 ...
2
votes
2answers
960 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 ...
1
vote
2answers
385 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
votes
1answer
25 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,...
0
votes
0answers
10 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
...
0
votes
2answers
30 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 ...
0
votes
0answers
24 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/...
1
vote
1answer
31 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 ...
0
votes
0answers
17 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
1answer
81 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
1answer
46 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 ...
1
vote
1answer
41 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. Iād like to connect these up to each other and form ...
0
votes
1answer
53 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?
0
votes
0answers
17 views
NAT syntax comparison
Could I know if the NAT syntax on ASA5510 v9.1.7 should be the same on ASA5512 v9.9 or v9.12.3 ?
Hope to get your answer.
Many thanks
1
vote
1answer
133 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-...
0
votes
1answer
37 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 ...
0
votes
2answers
51 views
Why we define pool for declaring CISCO router DHCP?
In case declaring DHCP server in CISCO routers, should define pool with network addresses.ā
Example
Router(config)#ip dhcp pool net1
Router(dhcp-config)#network 192.168.1.0 255.255.255.0
The router ...
0
votes
1answer
26 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 ...
7
votes
1answer
816 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 ...
0
votes
2answers
31 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
vote
1answer
53 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 ...
4
votes
3answers
26k views
Meaning of the ip default-gateway L2 switch
What is meaning of the ip default-gateway command on a Cisco L2 switch? I read something about it on the Internet, but there was written that it allows you to Telnet to the switch. I am little bit ...
0
votes
1answer
18 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 ...
2
votes
1answer
44 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
votes
2answers
54 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 ...
3
votes
2answers
1k views
Cisco IOS pick default route from two DHCP interfaces with track
I plan to have a portable IOS cisco router which will have two DHCP assigned ISP addresses from unknown ranges. A tunnel is then built through the preferred ISP to another outer.
I would like to set ...
0
votes
1answer
55 views
Cisco DHCP relay with Microsoft DHCP server
Current situation: we have a C3850 switch serving DHCP lease to desktop clients without communicating with any upstream DHCP server
Objective: We would like the C3850 switch continue to serve DHCP ...
2
votes
3answers
9k views
Show all VRFs link status summary
In Cisco IOS-XE if I want to see a specific VRF's bgp connections summary I would do:
show bgp vpnv4 unicast vrf VRF_ID summary
and the result would be as below example:
Neighbor V ...
0
votes
2answers
38 views
IOS. Whats the difference between these 2 commands
I am completing an online course for the network+ and am going through one of the labs. Here is a diagram of the network in question.
Specifically I have a switch with 24 fast ethernet ports and ...
2
votes
2answers
254 views
Restricting TFTP access from Host to Router using extended ACL in Cisco IOS
I am trying the below Extended ACLs to restrict TFTP but still I am able to upload files to the router using tftp. Not sure, what is wrong, can you all help?
Approach 1:
permit udp host <ip> ...
0
votes
1answer
37 views
When do ACLs on SVIs get applied on Cisco Catalyst devices?
I don't understand exactly when an ACL will get applied when on an SVI. Given the following (pseudo) configuration
int vlan 100
ip address 10.0.0.1 255.255.255.0
ip access-list in in
ip access-...
3
votes
2answers
121 views
How can I use an HTTP CRL on Cisco IOS?
On a Cisco 867 running IOS 15.6(3)M7, I'm trying to do the following:
TEST-GW1(config)#crypto pki trustpoint vpn-p2s-server-11
TEST-GW1(ca-trustpoint)#crl query http://myvpn/crls/21.crl
% URL must ...
2
votes
3answers
10k views
Changing Label for Generic PC in Packet Tracer
I can change easily Router and Switch names in Packet Tracer using hostname command in global config mode. But how could I change a label of a Generic PC, let's say from PC0 to Sales? i could not find ...
1
vote
0answers
46 views
Upstream QoS garanteed bandwidth
In the network I'm trying to manage there is a satellite link, the upstream of which is ~ 7 Mbps. In this upstream, I need to allocate 1.5 Mbps of guaranteed bandwidth for one single host, but nothing ...
5
votes
1answer
1k views
What is the effect of using “ntp allow mode control 0”?
I am attempting to mitigate the issues surrounding bug report CSCum44673. According to the software release notes found here, I need to ensure that all of my routers are on IOS version 15.2(2) or ...
0
votes
0answers
18 views
Is it possible to specify a bandwidth parameter per service instance?
I have a physical interface with multiple service instances and policer per service instance:
interface GigabitEthernet0/3
Ā switchport trunk allowed vlan none
Ā switchport mode trunk
Ā mtu 9192
Ā ...
1
vote
0answers
18 views
Configue IOS DHCP server to respond to Option 60 class
I have a number of small networks each with about half-a-dozen mostly-fixed hosts. The routers on each network provide DHCP service for the occasional visiting engineer's laptop. I am adding IP ...
0
votes
0answers
16 views
Rate limiting xFTP traffic originating from a Cisco IOS router
We have some routers on marginal cell links that we need to pull files from using TFTP or FTP. During file transfers connections to the router become so slow as to be unusable.
Is there a way to rate-...
1
vote
1answer
247 views
Lubuntu 18.04 can't SSH to Cisco Router: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1 [closed]
I'm not sure if this problem caused by Lubuntu or Cisco Router side.
Lubuntu = 192.168.1.100
Cisco Router = 192.168.1.1
Ubuntu 18.04.4 LTS
user@linux:~$ lsb_release -a
No LSB modules are available.
...
0
votes
0answers
125 views
Cisco erase nvram or erase startup-config doesn't work
According to this article, I can delete the current startup configuration files and return the router to its factory default settings with the erase nvram: and reload command.
https://www.oreilly.com/...
0
votes
1answer
84 views
Cisco IOS Sanitization: Any Way to Not Use NVRAM?
We want a method to sanitize Cisco IOS 15 routers (ISR Gen 2) before they are removed from the facility. While a "write erase" works perfectly if the router is breathing, how to sanitize dead routers ...
0
votes
1answer
62 views
Firmware of Cisco Phone
i want to configure IP phone Cisco DX650 with Sip.Anyone have idea about it how i can upload firmware of sip feature
0
votes
0answers
18 views
Cisco IE2000 - NTP Doesn't Associate
I'm having a very weird issue with a switch. It doesn't want to associate to my NTP servers.
My config is very simple:
ntp server ntp1.domain.com
ntp server ntp2.domain.com
ntp server ntp3.domain....
0
votes
0answers
13 views
What's the difference between “IP NAT Inside Source” and “IP NAT Inside Destination” commands in Cisco routers? [duplicate]
As much as i know both of this commands translate source address of packets that travel from inside to outside and destination address of packets that travel from outside to inside,so what's the ...
2
votes
1answer
33 views
Cisco snmp-server single user for multiple snmp versions
Attempting to maintain SNMP v2c compatibility while implementing SNMP v3 on cisco switch 5506cx.
Would a user that was previously used for v2c see issues with v2c if it is added to a v3 group?
For ...
2
votes
1answer
375 views
Link Aggregation from Cisco to Palo Alto using 10 gig interfaces, port on Cisco shows “waiting to be aggregated”
I am trying to bundle two 10-Gig interfaces on PA-3020 to Cisco Cat9300. Previously, I had bundled two Gigabit interfaces on same devices and everything worked fine. But now, when I try to configure ...
2
votes
1answer
65 views
Prevent static NAT to respond to ARP requests
We are trying to merge 2 networks with overlapping IP spaces: This is the configuraiton so far:
interface Tunnel1
description VPN Port CompanyA
ip vrf forwarding LAN
ip address 172.18.0.79 255.255....
2
votes
0answers
509 views
Cisco AIR-AP1852i-E-K9 stuck in “waiting for uplink[…]” after startup
I pulled an old cisco AP from a shelf today at work to test something, and after starting up and connecting with PUTTy, i was greeted with (after startup), this - repeating over and over:
[*02/16/...
0
votes
0answers
29 views
Cisco PPTP server available routes protocol
I have a 2921 Cisco router in one place, and a Windows XP computer on another.
I made my Cisco router as PPTP server, and my XP computer as a client.
The router is located within a LAN with address ...
0
votes
0answers
46 views
Cisco C3750 and PRTG netfllow
I have a core switch (backbone) of our network that broadcasts all the vlans to other switches. I am trying to configure netflow on the switch and link it up to a Netflow sensor on PRTG.
I followed ...
