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3

Connect the Airtel to the switch first. Then configure the Airtel with a free IP address on the same subnet as the other hosts and then change the default router on the three desired hosts which need to connect through the Airtel router. If you use DHCP on the LAN, make sure you have DHCP configured (disabled) correctly before connecting the Airtel device ...


0

You probably should look into port security topic here: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3560/software/release/12-2_52_se/configuration/guide/3560scg/swtrafc.html#wp1038501 Idea is that you can assign list of legit MAC addresses that are able to connect given port number without security warning.


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If you find that this issue pops up again, you may want to check the size of your DHCP scope and how many leases are in use. If old DHCP leases are not being destroyed, your server may think that there are no addresses left in the pool and be unable to assign new addresses. This is true even if there are no devices responding in the vlan. If your DHCP scope ...


1

For each VLAN, I needed a default gateway subinterface


2

Unicast flooding in and of itself isn't abnormal. A certain level of unicast flooding is going to happen as MAC addresses age out of the CAM (MAC address) tables on the switches. If you have excessive unicast flooding then I might posit that you have a problem with the Spanning Tree Topology of your switching infrastructure. The first thing I would suggest ...


2

I fixed the problem today by removing the vlan tag for the phone vlan on the port connecting to our dhcp server. It's very strange to me that this worked, as other systems that use a similar scheme (aka: Wifi SSIDs using 802.1q) require the tag or clients cannot get addresses. It worked, so I won't look too hard, but I would be interested in seeing answers ...


0

You should consider running a packet capture on either side of the problematic switch(es) and then reviewing this in Wireshark. This will be able to tell you 1) if traffic is being intercepted by a rogue DHCP server (based on MAC address) and 2) if something is getting mangled or dropped (eg, maybe you need DHCP relay). This may require port mirroring, or ...


0

While this is a little unconventional it should work. I've tried something similar before and did not get it to work, the PPOE server did not respond, however we had a fairly complex setup and also had firewalls in the mix. You may find the type and number of switches you have stops it working. Assuming you just have the one uplink cable between the two ...


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The monitoring port is not accessible over the network. he probably set all 48 ports as the monitoring port which made the switch unavauilable over the network. You would have to use the console port to undo the monitoring.


2

I generally install arpalert on a system for this purpose. It is a daemon, that uses libcap to watch traffic. It keeps a database of mac addresses per interface. It can also watch for some unusual types of events and send notifications. It keeps track of the last usage, and it will keep the database across reboots (in comparison to just setting up a ...


1

Well to be fair, everyone says "arp -a", but I am not satisfied with this answer, since it only shows the known MAC addresses (and their corresponding IP). To list all addresses on a port, you'll need to change your current network configuration. We will use the bridge-utils package, but any other bridge implementation (eg.: OpenvSwitch) can do this. The ...



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