Posts tagged "netwoking"
IP Scan Between Microsoft Clients on Port :7680 ?
TL;DR: If you experience poor network performance on your wireless notebook, Microsoft may be using your device as a download server without your consent. Problem : I noticed a high number of requests between Windows clients in different network zones on a customer's firewall. It appeared that allmost every client w...
Interface down on Cisco Nexus switch with "dcxNoACKi"
Problem: After an update of a server to Devuan4/Debian11the switch shuts down the interfaces to the server with status "dcxNoACKi" 48 minutes after the reboot. Discussion: the switch is a Cisco Nexus 5000 switch. It implements "Data Center Bridging Capability Exchange (DCBX)". The server is a Dell server with X710 C...
Linux Connection NAT Helper not Working
Some protocols need more than one TCP or UDP connection. For NAT to work the firewall needs to open additional ports to allow client server connection automatically. Examples are FTP (port 21 handshake, additional ports for data), PPTP (port 1723 for handshake, proto GRE 47 for payload) Since Linux kernel (~) 4.7 th...
Mikrotik OSPF Routing Distance Ignored
Discussion: Every routing protocol has a default distance to help the router to decide which route to use in case of multiple routes for the same destination. For Mikrotik routers these distances are listed here: https://wiki.mikrotik.com/wiki/Manual:Route_Selection_Algorithm_in_RouterOS If you want to configure a b...