Securing OSPFv2

glitchlist Blog Leave a Comment

OSPF is a king routing protocol that speaks on Multicast addresses 224.0.0.5 and 224.0.0.6. Once the neighborhood relationship is installed and LSAs are exchanged, the SPF algorithm starts running. If the new OSPF peer is a malicious router it can cause a lot of damage to your routing table such as: Network congestions Dos attacks Loops LSA flooding and why …

Juniper vs. Cisco Commands

glitchlist Blog Leave a Comment

JunOS IOS show chassis environment  show environment  show system processes show processes cpu request support information show tech show system connections show tcp show configuration show running config monitor start messages terminal monitor monitor stop terminal no monitor show chassisĀ  environment show environment all show interface terse show ip interface brief show log messages show logging show multicast route sh …

Cisco Catalyst vs HPE 5700 Link Aggregation

glitchlist Blog Leave a Comment

When you try to connect via Port Channeling Catalyst and HPE switches you should choose the same Link Aggregation protocol. HPE speak LACP, Cisco as a native language speaks PAGP but gets along well with LACP. To activate LACP under Cisco interface you have to usechannel-group [n] mode active command. HPE use instead link-aggregation mode dynamic under Bridge-Aggregation interface. bye! …

runts, giants and throttles

glitchlist Blog Leave a Comment

show interface is maybe the most famous command that is entered when we start troubleshooting.Interpreting the output of this command is like reading the results of the blood analysis, some results are easy to understand, while others are very cryptic but very useful to take us to another level of troubleshooting! Let’s see runts, giants an throttles: RUNTS are frames …

Cisco Catalyst – enable redundancy

glitchlist Blog Leave a Comment

Cisco Catalyst 4500/6500 series can host up to 2 Supervisor Engine in his chassis. Below a quick list of commands to set up redundancy between Supervisors Engines: In (config-r-mc)# section you can choose what sync with the stand-by supervisor but remember vlan-database is always syncronized! bye. .glitchlist crew

OSPF silent-interface

glitchlist Blog Leave a Comment

When you want to interconnect 2 OSPF processes in static mode for design requirements or just temporary in a migration scenario you have to instruct routers to not receive routing update information and to not advertize networks to another router. By default when you start an OSPF process all interfaces of the router send Hello packets to discovery neighborships. To …

Layer 2 Traceroute

glitchlist Blog Leave a Comment

There are some nightmares that could torment the life of an access network, one of them is the MAC FLAPPING. as a loop condition or sometimes rogue devices installation, you will spend your day chasing mac addresses around your network. this great function on switches firmwares can Help! On Huawei switches trace mac enable must be enable on all access …