Alternative to netcat in linux to test ports

While working on VMware Unified Access Gateway, we needed to test TCP/UDP port connectivity from within the appliance to a syslog server. The appliance did not have the usual go to tool, netcat. So, what are the alternatives to test port connectivity in Linux? Interestingly, you can use bash to test port connectivity for you, like below: To test tcp port connectivity to on port 514, use the command...

July 26, 2017 · 1 min · Jahnin Rajamoni

Restrict AD access to the vSphere Management Assistant

When vMA is added to active directory, be default, all users will be able to login to the appliance. In order to restrict the login to certain users or groups, we need to manually edit the Likewise configuration file located in /etc/likewise/lsassd.conf Look for the following section, uncomment “require-membership-of” and provide a comma seperated list of users, groups and sid’s that you would like to restrict access to. # Allow only the following users and groups...

June 10, 2015 · 1 min · Jahnin Rajamoni

HAProxy and VMware View

HAProxy is an open source load balancer. More info here: HAProxy can load balance HTTP/HTTPS and supports session persistence. The View Setup: Internal Network Subnet: 192.168.100.x External Network Subnet: 10.1.1.x Two connection servers with the below IP Addresses: Connection Server 1: Connection Server 2: Two Security Servers with the below IP Addresses: Security Server 1: Security Server 2: HAProxy Load Balancer server configuration: OS: Ubuntu Server 14....

November 5, 2014 · 2 min · Jahnin Rajamoni

Build your own Linux router

Things you need: 1. A Linux box 2. Two network adapters that connect to different networks that you wish to route. How: Enable IP Forwarding By default all modern Linux distributions will have IP Forwarding disabled. Use the following methods to enable and configure IP Forwarding. Check if IP Forwarding is enabled: We have to query the sysctl kernel value net.ipv4.ip_forward to see if forwarding is enabled or not: Using sysctl:...

May 12, 2014 · 2 min · Jahnin Rajamoni

Throttle SCP file transfers

Afraid that the scp transfer will eat up all available Bandwidth? To throttle scp file transfers, use the ‘-l’ parameter: For e.g.: To set the file transfer limit to 1Mbps scp -v -l 1024 useraccount@destinationhost:/path scp -v -l 1024 vmware.log root@

May 12, 2014 · 1 min · Jahnin Rajamoni