Key Change for Cisco IOS 15 — Feature Licensing and How We Work.

Welcome to IOS 15, Feature licens­ing and com­plic­ated main­ten­ance procedures.…

Cisco Announces EOS and EOL Cisco IOS Software Release 12.4

Cisco announces the End of Life and End of Support dates for 12.4. Before IOS 15.0 is even warm­ing up, the pre­vi­ous ver­sion of 12.4 is already on life support.

The Poor Man’s IOS Traffic Generator

This is a fea­ture that I used to use years ago, but had for­got­ten about. For some reason, I remembered it today and it is still as use­ful as it ever was. Read on…

IOS CLI: Show Run Linenum

This Post is Part of a Series  —  click for list on Console Mastery» You prob­ably know this one already, but I have been typ­ing “wr t” for a long time and never stopped to look. Puts a line num­ber at the side of the con­fig so you can say to the per­son on the other end of the phone, see […]

Cisco IOS Order of Operation — Updated, Again

I often need to refer to the IOS order of oper­a­tion when I start stack­ing mul­tiple func­tions in an IOS configuration.

Changing the Break Character in Cisco IOS

Does press­ing “Ctrl-​​Shift-​​6 & x” bother you ? It bugs the hell the out of me.

IOS: Setting the TCP Timeout on IOS

One of my favour­ite default com­mands on IOS is “ip tcp syn­wait 5″. Lets look into this com­mand and why you might like to use it as well.

IOS: Enable and .… Disable ?

This Post is Part of a Series  —  click for list on Console Mastery» All these years, and I didn’t real­ise the oppos­ite of the enable, was dis­able.
List of Posts in this series:Serial Console on OSXIOS: Reverse SSH con­sole access  —  Part 2IOS: enable and .… dis­able ?IOS: Setting the TCP timeout on IOSIOS:CLI Tip  —   ter­minal full help OS X:Terminal break for Serial […]

IOS: ROMMON on the C6500/​Sup720 — Lesson Learned

Recently, one of my Supervisor 720 goes into a per­man­ent reboot cycle. I was able to break it into ROMMON mode, but I couldn’t get it to ‘stick’ the boot set­tings.
Finally.…

IOS: Reverse SSH Console Access — Part 2

Following my ori­ginal post about con­fig­ur­ing Reverse SSH on a Cisco con­sole server, I wanted to make some fol­lowup to extend the usage.

Configuring Windows 2003 /​ XP SP2 to Use IOS NTP Server

In cer­tain net­works, it is dif­fi­cult to get the time on your serv­ers to be exactly the same as the NTP time on your net­work equip­ment. In this case, you want to force the Windows serv­ers to use the same NTP Network time source as your routers and switches. But Microsoft Windows doesn’t under­stand NTP […]

IOS:Open Source Lab DNS and IP Addressing

A num­ber of Cisco Bloggers have talked about mak­ing labs avail­able for oth­ers to use. However, part of what will be needed is some con­ven­tions to make these labs work for the largest num­ber of people.
Following Ivan Pepelnjak post­ing on Private Domain Names, and an earlier post­ing that I made on Reserved IP Address […]

IOS: Reverse SSH Console Access

I recently needed to secure the reverse con­sole access using Cisco IOS router. Now for many years, we have been doing this over tel­net and the con­fig­ur­a­tion has been straight­for­ward. But con­fig­ur­ing it to sup­port SSH instead of tel­net is a little bit dif­fer­ent, awk­ward in fact.

Ip Tcp Timestamp

ip tcp timestamp
I have seen this com­mand a few times, today I am going to look into it and see what it does. Also, this is prob­ably a clas­sic CCIE lab gotcha.

Bidirectional Forwarding Detection  [Cisco IOS Software] — Cisco Systems

BFD is a most use­ful fea­ture of IOS, and IMHO, a much unloved fea­ture. I notice that latest releases of IOS now have BFD for static rout­ing, but more import­antly now supports HSRP

standby bfd
Example:
Router(config-if)# standby bfd
(Optional) Enables HSRP sup­port for BFD on the inter­face
standby bfd all-​​​​interfaces
Example:
Router(config)# standby bfd all-​​​​interfaces
(Optional) Enables HSRP sup­port for BFD on all interfaces.

Bidirectional Forwarding Detection  […]

On the Death and Rebirth of IOS — Why Did It Take So Long ?

The mar­ket has been com­ment­ing on the rise of Juniper for some years and the fact that Cisco has not been able to stop them grow­ing. Well, we can now see that Cisco was listen­ing to the stock mar­ket by spend­ing a lot of time and money devel­op­ing a new oper­at­ing sys­tem. Oh yeah, and some new […]

Single Internet Connection but HA Infrastructure — Using Bridging Instead of Routing

The cus­tomer had decided to build a host­ing plat­form, but could only arrange for a single inter­net con­nec­tion to that site due to loc­a­tion. However, all other hard­ware was duplic­ated for high avail­ab­il­ity. After con­sid­er­ing the options the fol­low­ing dia­gram was pre­pared show­ing the first pass at the design. This was the Internet Connection (100Mb Ethernet) con­nec­ted to the router, then con­nec­ted to a switch, which was inter­con­nec­ted by trunk to a second switch. The first layer of fire­walls is then connected.

Cisco ASA and IOS Command Tip — Test Aaa-​​Server

I have been work­ing on a VPN setup that loads the Group Policy from a CiscoSecure ACS server. During the pro­cess I dis­covered the test aaa-​​​​server com­mand. Its very handy tool when you are doing this kind of stuff.
Read on.….