TalkTalk traffic interception

Recently I was really annoyed by my ISP (TalkTalk @ UK). In short: They are intercepting traffic and doing deep packet inspection without any warning or approval. But wait, there’s more: In general they monitor web traffic (read: the data) and after intercepting an HTTP request the replay that (yes.. they replay the request). Here’s …

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Linux ethernet driver ring buffer

While performing some tests with a congested 10Mbps link, a strange thing happened: The link was congested only on one direction and both endpoint queues were RED queues. Based on the parameters and the queue size, the delay between those two links should be something near 170ms. However, the delay was much larger: >300ms (!). …

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How to disable CDP-4-NATIVE_VLAN_MISMATCH (native vlan mismatch)

Cisco switches support CDP and use it to help us in a number of ways. One of them is to detect native VLAN mismatch between two connected ports. For 99% of the time this is a “good thing to do” ™ but there are some corner cases where this is not what you want. For …

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Routes with greater prefix and Proxy ARP ~= IP Mobility

Inside an Autonomous System, it is possible to move a machine inside a network, keeping its IP address even though it goes to a network segment that doesn’t serve the corresponding Network. Something like this: RouterA ——– Network Segment | Host A (10.1.0.2/24, GW: 10.1.0.1) It is possible to move Host A to another network …

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