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October 1st, 2024 12:10

shutting down a port on a N1548 switch should turn it off, right? :)

So i have a stack with 2x N1548 and one N1524P. One of the N1548 is the master.

A certain server is connected to port Gi/1/0/38 there.
I have double checked that the mac of the IP of that server is right there.

So i do

enable
conf
interface Gigabitethernet Gi1/0/38
shutdown

But the IP still answers ping. What could be wrong?

When i check with this

show interfaces gigabitethernet  1/0/38

It says
...

Link status... shut   /None


...

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9.5K Posts

October 1st, 2024 18:49

Alexander-36725,
 
Would you confirm how long after performing the shutdown you tried pinging it? I ask as the switch will still respond to ping requests for a brief period after the port is shut down, typically up to 30 seconds, before it is fully disabled. This is because the switch's operating system and forwarding processes take some time to recognize and propagate the port change, and the delay can be longer with the presence of an ARP as well.
 
Also, I would make sure that server doesn't have any other connections to the network.
 
Let me know what you see and if this helps.
 
 

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106 Posts

October 3rd, 2024 07:35

Its still pingable... And yes, it (that server) sure has other connections going on, its a server serving and doing stuff :)

But does this mean that "shutdown" simply doesnt work? I mean, in essence i kinda have to turn the server off to disable the port (?), which very much defeats the purpose.

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2.8K Posts

October 3rd, 2024 09:10

Hmm... just thinking, switch might still remember the server’s IP address and link it to the server’s MAC address, even though the server is turned off. This could be causing the connection issues. Could it be related with arp list? You can check "no arp ip access-list acl-name" or "arp delete <IP address>" commands. 

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106 Posts

October 4th, 2024 07:00

Ok, so i tried just "show arp", and it only shows 3 IPs (that server is not one of them).

It should show many more IPs by the way, there is a bunch of servers connected to that switch (stack).

All these 3 are management IPs (the first two are know to me, and the last third is some internal mgm IP i guess?)

Also, i seem to have "arp purge" and not "arp delete" on this switch. Its an N1548 switch.

mlmsw4-1>show arp    

Static ARP entries are only active

when the IP address is reachable on a local subnet

Age Time (seconds)............................. 600

Response Time (seconds)........................ 1

Retries........................................ 4

Cache Size..................................... 893

Dynamic Renew Mode ............................ Enable

Total Entry Count Current / Peak .............. 2 / 2

Static Entry Count Configured / Active / Max .. 0 / 0 / 16

IP Address       MAC Address        Interface       Type      Age

---------------  -----------------  --------------  --------  -----------

10.10.253.1      CC96.E5EB.04B6     Vl1             Gateway    0h  0m 18s

10.10.253.41     684F.6453.1912     Vl1             Local         n/a

250.251.252.254  0202.BC80.0002     Management      Dynamic   n/a

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2.8K Posts

October 4th, 2024 08:42

Thanks for checking it. You mentioned stack, if there is any redundancy or alternative paths in your network, traffic can reach the server via a different route. This comes to my mind though not sure.

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