rohan-molloy

Problem

2023-09-27T10:52:26.802Z In(05) host-3241276 Using kernel build system.
2023-09-27T10:52:26.802Z In(05) host-3241276 /tmp/modconfig-MRgyG5/vmnet-only/bridge.c: In function ‘VNetBridgeSendLargePacket’:
2023-09-27T10:52:26.802Z In(05) host-3241276 /tmp/modconfig-MRgyG5/vmnet-only/bridge.c:1413:11: error: implicit declaration of function ‘skb_gso_segment’; did you mean ‘tcp_gso_segment’? [-Werror=implicit-function-declaration]
2023-09-27T10:52:26.802Z In(05) host-3241276  1413 |    segs = skb_gso_segment(skb, 0);
2023-09-27T10:52:26.802Z In(05) host-3241276       |           ^~~~~~~~~~~~~~~
2023-09-27T10:52:26.802Z In(05) host-3241276       |           tcp_gso_segment
2023-09-27T10:52:26.802Z In(05) host-3241276 /tmp/modconfig-MRgyG5/vmnet-only/bridge.c:1413:9: warning: assignment to ‘struct sk_buff *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]
2023-09-27T10:52:26.802Z In(05) host-3241276  1413 |    segs = skb_gso_segment(skb, 0);

rohan-molloy

Network Isolation of Services with Systemd

Network namespaces are an important component of containerization in Linux. A network namespace (netns) allows a running process to see different network interfaces, routes, and firewall rules from the rest of the system. There are a number of use cases for network namespaces, such as running multiple servers, testing/staging environments and providing isolation of services.

Creating a Network Namepsace

We begin by creating a generic systemd service for creating a named network namespace. I add the following to /usr/lib/systemd/system/netns@.service. In systemd, the @ mean the service takes a parameter which is passed to the unit via %i. E.g, we can run sudo systemctl start netns@webserver.service.

rohan-molloy

# d899b42486eb805b8e432c5758568db487c6bcfc067d6ca7e1292a5a66d66de6  unbound.conf
server:
    # Listen on tcp 443,853
    interface: 0.0.0.0@853
    interface: 0.0.0.0@443

    # Allow from anywhere
    access-control: 0.0.0.0/0 allow 
    access-control: ::0/0 allow 

rohan-molloy

ICMPv6 Firewall Rules

Allow in ICMP messages (highly recommended)

ip6tables -A INPUT   -p ipv6-icmp -m icmp6 --icmpv6-type 128 \
-m --comment Permit-EchoRequest   -j ACCEPT

ip6tables -A INPUT   -p ipv6-icmp -m icmp6 --icmpv6-type 129 \
-m --comment Permit-EchoReply     -j ACCEPT

rohan-molloy

import requests
import os
import uuid
import hashlib
def download_file_hash(url, extension='txt'):
    response = requests.get(url)
    if response.status_code == 200:
        sha256hash = hashlib.sha256(response.content).hexdigest()
        filename = f'{sha256hash}.{extension}'
        with open(filename, 'wb') as file:

rohan-molloy

Disable Teams Autostart

1. Create the file C:\Windows\System32\GroupPolicy\User\Scripts\Logon\disableteams.cmd with the following contents

%WINDIR%\System32\WindowsPowerShell\v1.0\powershell.exe -File %WINDIR%\System32\GroupPolicy\User\Scripts\Logon\disableteams.ps1

2. Create the file C:\Windows\System32\GroupPolicy\User\Scripts\Logon\disableteams.ps1 with the following contents

$entry = $null -eq (Get-ItemProperty HKCU:\Software\Microsoft\Windows\CurrentVersion\Run)."com.squirrel.Teams.Teams"
if ( !$entry ) {

rohan-molloy

vmware:
    -
        name: 'VMware NSX for vSphere'
        serial: null
        url:
            - 'http://software.onthehub.com/shared/publisher/VMware/VMware-NSX-Manager-6.2.0-2986609.ova'
    -
        name: 'VMware vRealize Suite 7 Enterprise'
        serial: null
        url:

rohan-molloy

#!/bin/bash

# Variables
LINK='enp0s20f0u4u3'
ADDR='192.168.8.100/24'
NETNS='testns'
BROWSER='chromium-browser'

# Create the network namespace
echo "Creating ${NETNS}" 1>&2

rohan-molloy

export DOCKERVERSION=20.10.5
curl -fsSLO https://download.docker.com/linux/static/stable/x86_64/docker-${DOCKERVERSION}.tgz \
  && tar xzvf docker-${DOCKERVERSION}.tgz --strip 1 \
                 -C /usr/local/bin docker/docker \
  && rm docker-${DOCKERVERSION}.tgz

rohan-molloy

Installing VMWare Workstation 16 on Fedora 33

1. Download from https://www.vmware.com/go/getworkstation-linux

2. Elevate to root

3. Create a wrapper script

#!/usr/bin/bash