The operating system used on the majority of Cisco's routers and switches; a package of routing, switching, internetworking and telecommunications functions tightly integrated with a multitasking operating system. For Apple's mobile device OS, use apple-ios.
Questions tagged [ios]
309 questions
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Will cisco 3750-e switches run the old ipservices ios code?
was wondering about cisco 3750-e switches. Will they run the old ipservices ios code? Or do they only run the univeral image?
Thanks
Jude
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1 answer
ios: how to stop output of a show command
Can anyone tell me how to break output of a show command in cisco ios?
Say I don't want to see all of 'show run' and I got the info I need, what keys can I press to stop it from printing the rest of the output?

blsub6
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3 answers
Configure hairpinning on Cisco 871 IOS 12.4(15)T4?
I'm a newbie to IOS. In the past I've used consumer routers which seem to have the smarts to automatically route requests to internal hosts addressed by their public name back to the internal network. I think this is called hairpinning.
I need to do…

Emmanuel
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Cannot login to Cisco 2911 over ssh?
30 minutes ago my router is not accepting ssh connection. Well, ports is open (due to nmap), ssh simply hangs on reading from Cisco socket (observation from strace):
/home/rafal/.ssh/id_dsa-cert type -1
) = 60
open("/etc/passwd", O_RDONLY|O_CLOEXEC)…

bluszcz
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Can't enable IPv6 in Cisco 2800 router running IOS 12.4T
I can't enable IPV6 in a Cisco 2800 router that runs iOS version 12.4T.
I followed the summary steps section in Cisco's web page . But whenever I type "ipv6" on the command line (as in 'ipv6 address' - Step 4 in the summary steps), I get an error…

Ganesh
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More than 8 classes in a policy-map - Cisco 3560
It appears I am limited to 8 classes per policy-map.
Here is the error message when using the Cisco Network Assistant:
The policy "policy-name" contains more
than 8 policers, which means it cannot
be attached to interfaces. Are you
sure you…

jman
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Cisco T1 Routing Help
Thanks to someone on this site I was able to get the Serial0/0 interface up. I now have:
DCD=up DSR=up DTR=up RTS=up CTS=up
My next challenge seems to be in the routing and/or PC ip setup.
This are the pertinent details from L3:
WAN Network:…

Joseph
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1 answer
Cisco 2911 - problem with DHCP
i am configuring DHCP daemon on Cisco 2911.
At some point i assigned address 192.168.50.50 to one box (using MAC address 'relation').
When I wanted to saved config - I got warning, that address 192.168.50.50 is already in Pool, which sounds bit…

bluszcz
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4 answers
How to start Cisco 2911 with presaved configuration?
I briefly configured branch router Cisco 2911 and saved config.
Unfortunately - after rerun Cisco needs "copy startup-config running-config" to read configuration (I really need this - for example to get up interface GigabitEthernet0/0).
How I can…

bluszcz
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Cisco 851 (IOS) router: FastEthernet 4 (WAN) got the shutdown flag
At a customer location there was a Cisco 851 router (which uses IOS). The PCs on location were all of a sudden unable to connect. We came on site and found that FastEthernet 4 (the WAN port) was "administratively down". We ran these commands to…

700 Software
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1 answer
BVI vs Bridge routers
What is the difference between BVI and Bridge on Cisco IOS routers?

700 Software
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Cisco IOS ACL: Don't permit incoming connections just because they are from port 80
I am going much based on my memory and I may not be correct on all of this.
On a Cisco 851 (IOS) that uses a BVI or a bridge-route (the servers on the inside are configured with static and public IP addresses). I would apply two access lists (both…

700 Software
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3 answers
Why do Cisco IOS routers hang in the middle of large downloads?
After a few years in use. We have seen Cisco 871 and 851 routers that would hang if you had a single download that was more than 100M large. It is intermittent. Sometimes the problem goes away, sometimes it happens on very small downloads (just a…

700 Software
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1 answer
Restrict NAT in IOS to only one public IP
I've managed to enable port-forwarding on my Cisco 877 but I wasn't able to find a way to specify a single accepted IP from the outside. Any link to a Cisco documentation or commands to type in IOS are welcomed.
Thanks by advance.

Laurent Nominé
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3 answers
Can't connect to PPTP server outside of network
I'm trying to configure my Cisco 881 running IOS 15 to allow pptp connections to servers outside of the network. I know the PPTP server is configured correctly, because a)it's a clients VPN, and b) it works when connection from outside of the 881. …

Dan McClain
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