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How does this pc get an ip?

Xavier Jackson
Level 1
Level 1

Hello. 

This is probably a stupid question as im very new to networking and its confusing me.

So ive connected my pc to a wallport using an ethernet cable which connects into a switch.

I hopped onto the switch and saw the interfaces running config is that it is an access port and in vlan 117 which is the data vlan. This vlan is an SVI. 

The interface does not have a manual ip address on it. 

I then checked 'show ip dhcp pool' and couldnt find any of the range that my pc got its ip from. And i also did a 'show ip dhcp binding' and i dont see anything with my IP address. On my pc doing an ipconfig it shows (preferred) next to the IP i got. 

 

Doing a show ip arp | inc [My NIC Mac Address] and i can see the IP.

Im hesitant to share output as its a company switch. I mainly just want a general idea of how it works. Manually configuring IPs on an interface i understand but im a bit stumped on how its got an IP with no manual IP and is working with no DHCP pools for that ip range on the switch. Unless theres a relay agent somewhere. 

3 Replies 3

Martin L
VIP
VIP

When u wrote "interface does not have a manual ip address on it. " did u mean SVI interface 117 or access port interface in vlan 117 that connects to PC?

Is there upstream server or a router that has dhcp service on ? 

ipconfig on PC shows leased or obtain from,  via  dhcp ?

Regards, ML
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balaji.bandi
Hall of Fame
Hall of Fame

ipconfig /all  output give you where the IP served to PC.

DHCP Server . . . . . . . . . . . : 192.168.1.X

May the Switch you connected Layer 2 - there may be in the network you have Layer3 and DHCP Server  (this what we can see in the Dark)

Not  Sure  what you expecting community to help here with out providing information what you have.

 

BB

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Joseph W. Doherty
Hall of Fame
Hall of Fame

What's the PC's OS?

Reason I ask, Windows will self assign an IP.

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