So as many of you know who have used it in the past netflow is a great tool. Netflow gives you detailed information about traffic flowing through your routers. You can find out what IPs the traffic is coming from and going to, you can see what protocols, what ports and how much traffic is […]
So if you are multi-homed on BGP and you want to be able to decide yourself which path incoming and outgoing your traffic will take you will need to make a few changes. By default BGP will try to make the best decision on what path to take. Problem is a lot of time it […]
So I just started a job for a new company. One of the first things I did was look for easily resolvable issues on the network. Some symptoms to look for are any packet loss or high latency on a local LAN link, CRC errors on your switch ports and router ports, ultra slow RDP connections, […]
If you are like me you like to take a running-config dump it to a text file open it in a text editor before making any major changes. You can then plan out all the config changes you want to make and save it to a separate file so you have the current config and […]
“A coalition of companies have banded together to put a functioning piece of the Internet infrastructure into space: the router.
While network data has seamlessly passed through the ionosphere and back to Earth as part of getting from terrestrial Point A to Point B on the Internet, network packets have not been routed in orbit. With […]
So ICMP is a double edge sword, it is great for helping you troubleshoot network issues and verifying the most basic connectivity is working. It also can give away a lot of information about what is going on in your network to people who shouldn’t know.
The question then becomes what kind of ICMP types do […]
Had some routers automatically change and some routers not change there time this weekend so I put in a workaround to get them all to play nice with this DST change. These commands are for IOS.
Remove the line “clock summer-time CST recurring” from your config. (You might have to change the timezone in your command)
Add […]
Recently I was working on adding a new /24 network into our BGP advertisement networks. I added the new network into the network list under the BGP config, I added it into my prefix-list and route-map that restricts what networks we advertise to our BGP peers.
When I checked what routes were being advertised using the […]
When you add a static nat in your Cisco router for one of your servers the router then knows the internal and external IP. When you do a DNS query on that server to an outside DNS server the router will translate your returned address to the internal IP for you. See below for the […]
I have put a service-policy in place on my companies high speed WAN link to control how much bandwidth the backup servers can use. This is a time-range based policy so that at night the backups can use as much bandwidth as is available and during the day it can only use 40 Mbps.
Scrubed config
time-range […]
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