Author Archives: Robert

Error-Disable

When a network port encounters an error. This port is automatically shutdown to ensure network stability. When error-disable is enabled. The predefined error are as follows; arp-inspection bpduguard channel-misconfig dhcp-rate-limit              gbic-invalid                 l2ptguard                   link-flap mac-limit link-monitor-failure loopback oam-remote-failure pagp-flap port-mode-failure psecure-violation … Continue reading

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SSH error on cisco router

Enabling SSH on a Cisco router is not enough to guarantee SSH is working. Enabling ssh version 2.0 on a routers is as straight forward as;. >ip ssh version 1-2 I surely recommend the use of version 2, because ssh … Continue reading

Posted in CCNP

DHCP Helper address

Which source ip address is used when relaying a dhcp-request ? Continue reading

Posted in CCNP, GNS3 | Tagged , , , | 1 Comment

GNS3 caveat – port status

Creating a network lab in GNS3 is reliefs on budget. But there are some drawbacks. One of which is port status. I have noticed that using GNS3 in combination with iouyap results in some unexpected behavior. Once a topology is made … Continue reading

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Extended IP Access-list

As we all have learned in our pursuit to CCNA there are many different types of access-list. In reality most commonly used are ip access lists. Major difference between ip standaard access-list an ip extended access-list is the ability to … Continue reading

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EIGRP neighbors

Cisco EIGRP protocol allows different methods to form neighborship relations. Default method is form neighborship automatically via multicast (multicast address of 224.0.0.10 is used) After an adjacency is formed ‘hellos’ are  sent using IP protocol 88 (eigrp). This means that; … Continue reading

Posted in Commands

Cisco Express Forwarding

Differences between IP CEF , fast forwaring and processor based forwarding. Continue reading

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