NBAR2 on Sup8E can assist in blocking BitTorrent. While somewhat useful, BitTorrent is mostly used for downloading pirated movies, and BitTorrent off someone’s ADSL line is usually dead slow. Create a class map and a policy map as shown below, and attach that policy map to your ingress interfaces, and BitTorrent should be blocked. class-map […]

Read More → Using QoS for blocking BitTorrent on Catalyst 4500E Sup8E

The official documentation on Cisco IOS XE for Catalyst 4500E claims this is the syntax for specifying IPv6 RDNSS and DNSSL: Switch(config)# interface Te1/1 Switch(config‑if)# ipv6 nd ra dns server 4::4 Switch(config‑if)# ipv6 nd ra dns search list Using IOS XE 3.10.0E, the correct syntax for DNSSL is: Switch(config)# interface Te1/1 Switch(config‑if)# ipv6 nd ra dns server 4::4 Switch(config‑if)# ipv6 nd ra dns‑search‑list domain Sadly, the quality of Cisco’s documentation isn’t what it was back in 2006.

Read More → IPv6 RDNSS and DNSSL on Cisco IOS XE

At work we switched from a Cisco Catalyst 3560G to a Catalyst 4500E a few weeks ago. Remember to issue the spanning-tree extend system-id command prior to enabling VTP version 3. During the test period, the Icinga instances logged packet losses of varying degree around the clock when doing ICMPv6 pings.

Read More → Lessons learned on Cisco Catalyst 4500E