Category: Troubleshooting
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NAT’s interaction with DNS answers
Recently I was troubleshooting some odd DNS results between 2 customers that have a B2B connection. The DNS record in question existed in the wild on the internet and resolved to 113.129.255.98 (all IP’s have been randomized using https://onlinerandomtools.com/generate-random-ip for anonymity). Customer A resolved to 192.168.20.5 on their end of the link and Customer B…
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NTP redesign
This post is about a bug that affected NTP (Network Time Protocol) and our redesign of the environment bypass the issue. In this environment the core Cisco 7604 IOS routers were the NTP stratum 2 servers (x.x.x.123 because fun with port numbers). The IP was an HSRP standby IP. There were several downstream Linux…