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dhcp trouble with 2 switches

post #1 of 11
Thread Starter 
I installed a new switch in our warehouse because our office switch ports are full. Our network now looks like this:

server (dhcp) - office switch - warehouse switch - warehouse computers

Both switches are cisco sg200. Office is 26 port. Warehouse switch is 18 port. The dhcp server gave an ip to the new switch and I can connect to the web cli no problem but and PCs connected to the warehouse switch are not getting IPs from the dhcp server. Firmware has been updated on both switches. Any suggestions?
Edited by mrsmoke - 5/2/15 at 6:17pm
post #2 of 11
Same VLANs between switches? Did you allow the VLANs down the trunk between the units? Can you access the other switch using a configured in band management address over that same link?
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post #3 of 11
Thread Starter 
Both switches are on vlan 1. I can connect to both switches via web browser to administration panel. Dhcp gave ips to both switches. Nothing after the second switch is getting an ip.
post #4 of 11
run wireshark on one of the PC's and filer on bootp.

run the below in cmd

ipconfig /release && ipconfig /renew

attach the wireshark trace so we can take a look. im guessing that you and ping the DHCP server fine from the warehouse PC's and the switch???
post #5 of 11
If you assign a static IP address to any computer connected to switch 2, are you able to access ALL LAN resources and the internet?

When you say both switches are on VLAN1, you mean that both switches are configured with no VLANs, and all ports are untagged?
post #6 of 11
Quote:
Originally Posted by Ippy2 View Post

If you assign a static IP address to any computer connected to switch 2, are you able to access ALL LAN resources and the internet?
+1 on this suggestion.
If that works, either your warehouse switch is blocking DHCP - not that a layer 2 device can, or should be, blocking layer 3+ communication, but that's just me - or your DHCP server has run out of IP's to delegate, either through a maximum lease limit, or a too small subnet.
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post #7 of 11
Can you export the working config to a TFTP server and then inport it on the switch you are having issues with?
 
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post #8 of 11
If you can ping just fine from a static address from the warehouse PCs and are not getting dhcp discover packets to the dhcp server in wireshark add IP helper-address on the vlan1 interface to forward dhcp packets across the warehouse switch.
post #9 of 11
Could he post his switch config on the forum so we could see it? That would narrow down the issue. Not to mention if they are new switches from Cisco, they should have SmartNet on them. I would call them and have them check out the config over a WebEx meeting.
 
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My desktop
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First Desktop
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CPUMotherboardGraphicsGraphics
AMD FX-8350 Vishera @ 4.86 Ghz 1.5V ASUS SABERTOOTH 990FX R2.0 AM3+ AMD 990FX EVGA GTX 660 TI 3GB EVGA GTX 660Ti FTW+ 3GB 
RAMHard DriveOptical DriveCooling
16 GB DDR3 1600 G.Skill Samsung Pro 850 256GB SSD LG BD Corsair H110i 
OSPowerCaseOther
Windows 7x64 Professional CORSAIR HX Series HX750 750W ATX12V Antec LanBoy Air 5 switch fan controller 
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AMD Phenom X4 965 Black Edition MSI NF750-G55 AM3 NVIDIA nForce 750a SLI HDMI ATX ASUS GTX 550TI 1GB 8GB 1333 DDR3 G. Skill (2x 4GB) 
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post #10 of 11

I know it's obvious, but I'm assuming you are not limited by your DHCP scope range or Subnet mask? Doesn't sound like you have 2,500 users like I do, so it's likely not that.

 

I have 75 DHCP scopes in my corporate HQ so we run into problems of that scale when someone decides to instantly hire 150 people (double the size of their department) and not tell IT.

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