macvlan host guest connectivity

There are a number of sites out there mentioning that macvlan has a limitation when used with docker or lxc containers. The host machine will not be able to communicate with the guest machine and vice versa. While this is true by default, there is a tweak that you can perform to make host guest ...

Public IP Hijacking over LAN

This is a topic that is not commonly discussed. Most articles about IP hijacking deal with the subject at the ISP level, i.e. hijacking of BGP protocol. However, IP hijacking can be performed on the LAN as well. It is possible to use static routes at the gateway to route a public IP address to ...

Migrating rsyslog to Splunk

I recently decided to migrate my server cluster's logging mechanism from rsyslog to Splunk. My previous setup was to use rsyslog to centralise all logging onto /var/remotelog/ on a central server. I then configured the Splunk indexer to index both /var/log/ as well as /var/remotelog/, this ...

Enumerate sites hosted on same IP

Enumerating sites which are hosted on the same IP address can sometimes tell us a lot about a server. Is it shared hosting? Is it a legitimate server which was compromised for C2 operations? Does the site owner have any other shady business dealings on the side? I am aware that there are sites ...

Replicating UVB-76

For the uninitiated, UVB-76 is a station that broadcasts coded messages over AM radio. It is still active with messages transmitted as recently as Oct 2016 and is speculated to be related to the Russian military. The transmission and tone generation equipment are from the analog era, hence I ...

IP Hiding and Cloaking for Services

It is relatively easy to hide the IP address of clients through the use of VPNs and proxies. However, it is a challenge for services since they need to be reachable by the clients. Imagine if your phone number changed at the stroke of midnight everyday, it would be very difficult for others to ...

Measuring Power Consumption

I have recently acquired an electricity usage meter off ebay and decided to measure the power consumption of some of my devices. For a device that costs just 15 SGD, it works wonderfully and can measure voltage, amperage and wattage. It is supposed to be able to calculate electricity cost once ...

Saturating 1Gbps bandwidth

My ISP recently gave me a free speed bump from 500Mbps to 1 Gbps. I wanted to test if it was possible to fully utilise the bandwidth on a single file transfer. Firstly, we need to look at the test file size. I settled on a roughly 500MB to 1GB file size to minimise the effect of TCP window size ...