Dealing with a very lightweight embedded version of busybox on Linux means many of the traditional commands are not available (bc, printf, dc, perl, python)
# note the ";exit" lists the first default route interface, as there can be multiple
function nmap-fingerprint_network_of_default_interface() {
default_if=$(ip route list | awk '/^default/ {print $5;exit}')
default_if_cidr=$(ip -o -f inet addr show $default_if | awk '{print $4}')
nmap -sP $default_if_cidr
}
Nmap supports CIDR-style addressing. You can append /<numbits> to an IP address or hostname and Nmap will scan every IP address for which the first <numbits> are the same as for the reference IP or hostname given.
For example, 192.168.10.0/24 would scan the 256 hosts between 192.168.10.0 (binary: 11000000 10101000 00001010 00000000) and 192.168.10.255 (binary: 11000000 10101000 00001010 11111111), inclusive. 192.168.10.40/24 would scan exactly the same targets.
The reason is that [Wayback] fritzcap (written in Python) sometimes crashes while doing the conversion of a phone recording, so then only the .pcap file is available. I still want to figure this out, but given my health situation, I might not be able to in time.
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Ralf Hildebrandt is an active and well-known figure in the Postfix community. He’s a systems engineer for T-NetPro, a German telecommunications company and has spoken about Postfix at industry conferences and contributes regularly to a number of open source mailing lists.
Best practices for Postfix–the popular alternative to Sendmail. Developed with security and speed in mind, Postfix has become a popular alternative to Sendmail and comes preinstalled in many Linux distributions as the default mailer. The Book of Postfix is a complete guide to Postfix whether used at home, as a mailrelay or virus-scanning gateway, or as a company mailserver. Practical examples show how to deal with daily challenges like protecting mail users from spam and viruses, managing multiple domains, and offering roaming access.
Even with lots of experience, one learns new things every day.
A while ago, I discovered checkbashisms which checks sh shel scripts (usually with extension .sh) scripts to they do not contain code specific to bash.
checkbashisms, based on one of the checks from the lintian system, performs basic checks on /bin/sh shell scripts for the possible presence of bashisms. It takes the names of the shell scripts on the command line, and outputs warnings if possible bashisms are detected.
Note that the definition of a bashism in this context roughly equates to “a shell feature that is not required to be supported by POSIX”; this means that some issues flagged may be permitted under optional sections of POSIX, such as XSI or User Portability.
In cases where POSIX and Debian Policy disagree, checkbashisms by default allows extensions permitted by Policy but may also provide options for stricter checking.
Tool for Checking /bin/sh Scripts for Possible Bashisms
checkbashisms performs basic checks on /bin/sh shell scripts for the possible presence of bashisms. It takes the names of the shell scripts on the command line, and outputs warnings if possible bashisms are detected.
Write lines consisting of the sequentially corresponding lines from each FILE, separated by TABs, to standard output. With no FILE, or when FILE is -, read standard input.
The Wiert Corner - irregular stream of stuff 