Stanley Krute
asked on
One computer can ping network gateway, but not DHCP Server / DNS Server -- others all fine
I had this question after viewing Can Ping Gateway but NOT DNS Server.
A client of mine has this same issue. The fix in "Can Ping Gateway but NOT DNS Server" did not work. I have applied all of the fix items noted in that thread, including the fix solution.
Some data:
Four computers in this office are just fine. They can ping the gateway located at 192.168.16.1. They can ping the DHCP Server located at 192.168.16.3. They can ping the DHS Server located at 192.168.16.3. I have attached the results of an ipconfig /all command here as the file ipconfig.good.txt.
One computer is having problems. It can ping the gateway at 192.168.16.1, but CANNOT ping the DHCP Server and DNS Server at 192.168.16.3. I have attached the results of an ipconfig /all command here as the file ipconfig.bad.txt
The problem happened out of the blue yesterday afternoon. The Windows error logs show no suspicious events during that time period. The machine has a clean registry and clean malware status.
All ideas invited.
-- stan
- - - - - -
Stanley Krute
Chief Technologist
Siskiyou Digital Inc.
stan@siskiyoudigital.com
530-905-0099
ipconfig.good.txt
ipconfig.bad.txt
A client of mine has this same issue. The fix in "Can Ping Gateway but NOT DNS Server" did not work. I have applied all of the fix items noted in that thread, including the fix solution.
Some data:
Four computers in this office are just fine. They can ping the gateway located at 192.168.16.1. They can ping the DHCP Server located at 192.168.16.3. They can ping the DHS Server located at 192.168.16.3. I have attached the results of an ipconfig /all command here as the file ipconfig.good.txt.
One computer is having problems. It can ping the gateway at 192.168.16.1, but CANNOT ping the DHCP Server and DNS Server at 192.168.16.3. I have attached the results of an ipconfig /all command here as the file ipconfig.bad.txt
The problem happened out of the blue yesterday afternoon. The Windows error logs show no suspicious events during that time period. The machine has a clean registry and clean malware status.
All ideas invited.
-- stan
- - - - - -
Stanley Krute
Chief Technologist
Siskiyou Digital Inc.
stan@siskiyoudigital.com
530-905-0099
ipconfig.good.txt
ipconfig.bad.txt
ASKER CERTIFIED SOLUTION
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Ok. a few things I can think of
- duplicate IP addresses
- duplicate MAC addresses
- ARP troubles on the switch/router.
On the computer that works. check in commandline "arp -a". Check the servers MAC Address with its IP. Is it corresponding?
How about the computer that does not work after 15 minutes. "arp -a" the same MAC and IP combo as the one who works?
try an USB 2 LAN Adapter instead a Wifi Adapter to analyse the problem if you have one.
ps: Do you use a cisco ASA as Firewall? If yes. I had straneg behavior in the past such like this. Fixed it with "sysopt noproxyarp inside" in the Cisco ASA's cli.
- duplicate IP addresses
- duplicate MAC addresses
- ARP troubles on the switch/router.
On the computer that works. check in commandline "arp -a". Check the servers MAC Address with its IP. Is it corresponding?
How about the computer that does not work after 15 minutes. "arp -a" the same MAC and IP combo as the one who works?
try an USB 2 LAN Adapter instead a Wifi Adapter to analyse the problem if you have one.
ps: Do you use a cisco ASA as Firewall? If yes. I had straneg behavior in the past such like this. Fixed it with "sysopt noproxyarp inside" in the Cisco ASA's cli.
ASKER
Thomas U !!! Thanks so much. You nailed it.
The network in this particular office is overly complex and badly set up. The business owners are going away over the holiday, and I'm going to come in to clean and simplify things for them.
Thanks for seeing that high-rent district low ipa number issue. Staring me in the face, and I missed it. The randomness of this error makes me think that other devices popping on and off the network were grabbing that ipa.
LOVE the power of the group mind at work !! Thanks again muchos muchos.
The network in this particular office is overly complex and badly set up. The business owners are going away over the holiday, and I'm going to come in to clean and simplify things for them.
Thanks for seeing that high-rent district low ipa number issue. Staring me in the face, and I missed it. The randomness of this error makes me think that other devices popping on and off the network were grabbing that ipa.
LOVE the power of the group mind at work !! Thanks again muchos muchos.
ASKER
Oh, and thanks for the mention of a USB 2 LAN adapter. Yep, I've got one. And yep, that makes sense, to stay LAN rather than introduce wifi into the possible problem space.
So you may have second DHCP Server in the network that gives out IP Adresses as well and conflicting with the rela DHCP server?
I am very interested what the problem was after you have solved it on site ;-)
regards
Thomas
I am very interested what the problem was after you have solved it on site ;-)
regards
Thomas
ASKER
Apropos of nothing, it was able to see 192.168.16.3 again, and all was well. Internet access and all local networking worked.
That lasted about 15 minutes. Then, it went south again. Could see 192.168.16.1, but no long 192.168.16.3.
Ah, random problems, one of Dante's deepest mephistophelean circles ....
This is a Dell Optiplex 390, with a Realtek RTL81XX PCI-E networking chip.
Gonna add a usb wifi adapter tomorrow and see how that does.