Configuration Example

Telnet Time-Out is killing me….

René Jorissen on October 22, 2008 0 Comments • Tags: #connection #ip #out #synwait #synwaittime #tcp #telnet #time #timed

Aaarrrgggghhh, I hate it when I would like to telnet into a device and enter the wrong IP address. This means, by default, waiting for 30 seconds before being able to correct the IP address and start a new telnet session, because there is no escape sequence. SW01#telnet 10.100.12.250 Trying 10.100.12.250 … % Connection timed out; … Read More

Configuration Example, Security, Switching

Layer 2 security

René Jorissen on July 6, 2008 2 Comments • Tags: #address #arp #attacks #bpduguard #dhcp #dynamic #hopping #inspection #ip #layer #mac #rootguard #source #spoofing #two #vlan

I attended the session layer 2 security, because I had some discussions about layer 2 security with one of my colleagues. We were discussing about using layer 2 security and especially implementing it in the environments from our customers. Looking at my/our customers, I don’t see environments where layer 2 threats would be immediate. But … Read More

Other stuff..., Switching

Port-channel Cisco vs. VMware ESX

René Jorissen on April 4, 2008 5 Comments • Tags: #balancing #dst #esx #esxtop #etherchannel #ip #lacp #load #loadbalancing #mac #portchannel #src #srcdstip #srcmap

I have had different discussions with different customers about the load-balancing algorithms between a Cisco switch, configured with a port-channel and a VMware ESX server using multiple NICs. Our VMware consultants always choose Route based on IP hashes as load-balancing algorithm. This means that load-balancing happens on layer 3 of the OSI model (source-destination-IP). In … Read More