No Gateway Address

[ASGill]

Hi All,

I have a weird issue going on here, we currently have one domain, four subnets, all with a single gateway. We have DHCP server which hands out IP Adds.

Recently i have been receiving alot of calls in regards to clients not being able to hook on to the network/surf the net/cant access outlook. After further investigation i realized that all the affected clients do not have the gateway address, they are able to have an ip add and also the subnet mask but the gateway addr is blank. I get abt 5 to 10 calls a day with this issue.

Anyone knows where the root cause might be lying?

Thanks in advance.

 

[monsterjta]

Is your DHCP setup to dish out a Defaul Gateway? Is it possible that there is another DHCP server on your network that you are not aware of? Have you installed any new routers that are possibly handing out addresses without authority?

 

[ShackDaddy]

Since you have four subnets, you must have four DHCP scopes. Is each scope properly configured to provide the unique gateway for each subnet?

 

[ASGill]

Hi All,

monsterjta, the dhcp is the one and only one that dishes out gateway addrs to clients, i've checked the settings on dhcp, and everything seems to be fine, just the way i configured it during initial launch. i dont think there any routers handing ips.

ShackDaddy, yes i do have four dhcp scopes and all have different unique gateways, however i did noticed that this issue is affecting only one particular scope.

 

[kbing]

What OS is the client machines?

when you type "ipconfig /all" within a command prompt, is the DHCP server IP address the same IP address of the DHCP you have configured to hand out IP's? If it is the same DHCP server - then are there any messages (yellow or red) in the event logs?

What version of server is running DHCP? Is there a service pack that you might need to apply for a known issue?

Perhaps you could try to delete the scope in question and re-create the scope. Then go to the PC, release the IP and renew the IP...what happens?

 

[ASGill]

Kbing,

All clients are on Windows XP SP2

I have already checked the clients affected using ipconfig /all and noticed that the DHCP server is the right one. Though i havent checked the event logs. will do that if

the DHCP server is running on a Windows 2003 Server box.

I have done re-creating the scope. still having the same issue

 

[basst]

Is the default gateway address on the same network as the clients?

 

[ASGill]

basst,

yes it is.

 

[IRudebwoy]

By any chance are you using 3com 4500 switches?

I've recently updated a few of my edge switches to the 4500's and with Win XP SP2 I've had to release/renew the leases on every PC connected before the gateway IP took hold. All other DHCP settings and options worked as advertised. Other clients were not effected and Win XP clients on other switches behaved as expected. A reboot of the PC doesn't fix it. Once the initial release/renew is performed all is well -- 6 months and counting. Furthermore, new clients don't seem to be effected, only the clients that a part of the initial roll out.

FYI: I have VLANs and IP interfaces defined with routing on the switch(es) which includes using the dhcp helper functions.

Have Fun!

 

[ASGill]

IRudebwoy,

No, we're using cisco 9250 series swithches on our network. Even after ipconfig /release and ipconfig /renew the gateway ip doesnt register.

 

[ShackDaddy]

Just an FYI:

If the address configured in the scope/server options for the default gateway is not a valid address, the clients will ignore it and will show a blank address when you do an "ipconfig". So it sounds like the clients are deciding that your gateway is no good. Can you think of any possible reason that they'd be doing that?

Why don't you actually post all the real details for that particular scope? Without those, people assume you've done something stupid, even though you know you haven't. I've gotten a lot of that lately myself.

ShackDaddy