03-22-2011 12:24 PM
HI
I'm trying to install my new Cisco SG300-20 switch into my Lan, but I'm not succeeding.
The SG 300-20 fails to connect to my router.
When the router is directly connected to the SG 300-20 I doesn't manage to get DHCP configuration. Any port that I try fails.
When I add an old unmanaged switch between the router and the SG 300-20, the SG 300-20 does manage to get DHCP configuration.
When I use a static IP-address on the SG 300-20 and the router is directly connected, there doesn't appear an operational gateway in the IPv4 setup.
Where do I look for a solution?
Might the SG 300-20 be faulty and should I return it?
A. van Egmond
Solved! Go to Solution.
03-22-2011 01:50 PM
A few things you can check are:
See if the system light is blinking. If it is it is at the default ip address. If it is solid the IP address has changed due to static assignment or DHCP.
If no link light is on or the system light is blinking, the reason it might not be pulling DHCP is due to a port negotiation mis-match. Try setting the port on the router or the switch to 100Mb full or what ever you like just to see if that helps.
Make sure you are also on the latest firmware.
Try to factory default the switch by holding in the reset button for 45 seconds.
Cisco Small Business Support Center
Randy Manthey
CCNA, CCNA - Security
03-22-2011 01:50 PM
A few things you can check are:
See if the system light is blinking. If it is it is at the default ip address. If it is solid the IP address has changed due to static assignment or DHCP.
If no link light is on or the system light is blinking, the reason it might not be pulling DHCP is due to a port negotiation mis-match. Try setting the port on the router or the switch to 100Mb full or what ever you like just to see if that helps.
Make sure you are also on the latest firmware.
Try to factory default the switch by holding in the reset button for 45 seconds.
Cisco Small Business Support Center
Randy Manthey
CCNA, CCNA - Security
03-23-2011 11:13 AM
Hi Randy
Thank you for your support.
I tried all the changes you suggested and one did actually work.
After reducing the port speed on the SG 300-20 port to the router to 100M Full the SG 300-20 could complete the DHCP configuration.
The only thing is I now have only a 100 Mb port speed instead of the 1 Gb I wanted. The router and all my other devices on the LAN and switch have 1 GB capable NIC's. Also the SG 300-20 sets a 1 Gb speed when auto-negotiating the port speed to my router.
So it appears there is something getting outside the tolerance boundaries from either the switch or the router when negotiating DHCP.
Is there any suggestion you could make to improve the DHCP configuration at 1Gb speed?
Are there any configuration parameters on the SG 300-20 that could improve this or is there anything Cisco could do in firmware to improve DHCP negotiation?
Looking forward to your reply
Alwin
03-24-2011 06:29 AM
Have you tried setting the negotiation to 1000Mbps full duplex?
Also you can try on the switch MDI/MDIX and manually set that as well.
What type of cable are you using? Cat5, Cat5e, Cat6?
How long is the cable? is it a crossover or straight through?
03-24-2011 11:08 AM
Hi Randy
Thank you again for trying to solve this with me.
I have tried the 1000M Full duplex directly from the beginning, but that doesn't work at all.
Because I'm still trying to get the SG 300-20 to work properly, I use a short 6 ft. Cat 6 cable to my router. When I can get it to function properly it will be on a 30 ft cable.
I use a straight through cable for connecting it to my router, the auto-negotiation comes up with MDI, but all devices have Auto-MDIX so that shouldn't be the cause of this DHCP behaviour.
By the way, when connecting an ordinary PC directly to the router using the same cable, it does immediately perform a DHCP configuration and the port speed is 1000M in that case.
So it appears the SG 300-20 is working outside of the ordinary specifications for a 1000 M port speed when trying to perform a DHCP configuration.
Would you advise me to return the device as faulty or do you think you or your colleagues at Cisco can get this SG 300-20 to act properly?
Regards
Alwin
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