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Showing posts with the label Networking

Irony

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My story begins with slowness, like many IT stories before it. Let me give some context. This is regarding a custom application hosted at an MSP. The problem started about a week after production launch. Staff and the broader customer base began experiencing slowness and timeouts. The usual answer ensues. "The servers look good" says MSP. "CPU doesn't go above 5%, tons of free memory, disk time is less than 1%, network utilization is low. It isn't anything on our side." Now with the onus successfully shifted, the problem lands internally. Pinging the application host at the MSP (MPLS circuit) produces a 1ms response time, impressive latency for sure. Next up, I was able to capture a "slow" event in wireshark: The first line is a query from my client to the server. The next two packets are from the server to my client. Strange result for a machine "doing nothing" as the MSP said. It took over half a second to start returning t...

Cisco VRF-Lite Guest Network and OpenDNS

My basic goal of doing this was to create a branded/managed OpenDNS enabled guest network on VRF-Lite. I didn't want to put any dependencies on the global routing process, I also wanted to avoid using any kind of OpenDNS Update Client for my cheapo adsl drop. In case anyone is curious this is a working config on c2900-universalk9-mz.SPA.153-3.M1.bin. Not sure why anyone else would ever try to do this, but this may be helpful if you do. ip vrf GUEST_VRF ip dhcp excluded-address 192.168.124.1 ip dhcp pool GUEST_NETWORK vrf GUEST_VRF network 192.168.124.0 255.255.255.0 dns-server 208.67.222.222 208.67.220.220 default-router 192.168.124.1 Create a vrf and guest network dhcp pool. ip domain lookup source-interface FastEthernet0/0/0 ip domain name guestvrf.net ip name-server 208.67.222.222 ip name-server 208.67.220.220 ip ddns update method DDNS_OPENDNS HTTP add https://USERNAME:PASSWORD@updates.opendns.com/nic/update?hostname=SITECODE interval maximum 0 1 0 0 I wanted...