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0x4C
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Server 2008 Network issues: Assumed Routing Issue

Hey,

I'm entirely new to ESXi and virtualisation but after going to a clients network the otherday and discovering some oddities I downloaded ESXi5 and am experiancing the same bizzare issues here.

Essentially the issue I found was that I could perform nslookup's against a short name fine but pinging or attempting to connect to a share over short name did not work.

Pinging or connecting to a share over FQDN DOES work as expected as does using an IP address.

I installed a fresh copy of ESXi5 and then brought up a VM running server 2008 here in the house.

Right from the install the machine couldn't ping itself or any other network device with a shortname but could perform nslookups.

Again pinging and connecting to shares works fine over FQDN and IP

Any help would be greatly appriciated and I apologise if this has been answered else where.

Dave

EDIT: I should add I've installed a copy of server 2008 on a standard machine in the house and shortnames are working exactly as expected.


Edit 2: I've looked into this more and my routing table shows Network 0.0.0.0 - Prefix 0 - Gateway 192.168.0.1.

This network has no switches, just simple hubs as it's just a testing home network. how can I fix this routing issue?

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Josh26
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0x4C wrote:

Here's a copy of the ping FROM the server trying to ping itself via shortname:

26956_26956.pngScreen Shot 2013-03-07 at 22.11.25.png

Dave

This is the magical screen shot Smiley Happy

The ping command is interpreting your hostname, 0x3c, as a hexadecimal number, and deciding that you want to ping 0.0.0.60. This isn't remotely valid, so ping generates an unknown error.

It's highly recommended that a Windows Server name starts with a letter, and you've found one of the strange bugs regarding why.

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Josh26
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0x4C wrote:

Hey,

Essentially the issue I found was that I could perform nslookup's against a short name fine but pinging or attempting to connect to a share over short name did not work.

Pinging or connecting to a share over FQDN DOES work as expected as does using an IP address.

Do you have these servers on a Windows domain, or are they just in workgroup mode?

If the latter, this would be somewhat expected behaviour.

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cdc1
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Short names usually get their DNS suffixes added using the value provided in the "Custom DNS Suffixes" tab when doing the management network configuration on the ESXi Console.

When you ping by DNS shortname, the host will append the DNS suffix listed in that field.  You can have more than one suffix in that field, seperated by comma (I believe ... but it's been a while since i've bothered to put more than one suffix in there.)

I would make sure that you put a DNS suffix in that field, as not having one there would definitely cause the behaviour that you're seeing.

In Linux and AIX (haven't used any other UNIX in ages, so can't vouch for those with any certainty) DNS suffix is a parameter set in the /etc/resolv.conf file.

In Windows, it's set in the Advanced->DNS tab of the IPv4 Properties window for your network connections.

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0x4C
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Josh:

It's just 1 Windows Server 2008 VM running DHCP, DNS & AD. The Server can't even ping itself using a shortname but will over IP or FQDN.

CDC:

The DNS Suffix list is populated correctly both on the ESXi Host and on the VM in question.

I still feel it has something to do what that routing table but I just can't figure it out.

Screen Shot 2013-03-07 at 12.05.12.png


Dave

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jdptechnc
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If the VM is running DNS, and the guest network adapter is configured to point to the local DNS server for name resolution, neither ESX nor routing should come into play at all, with regard the the VM not being able to resolve its own short name.

You said nslookup works with short name.  When you say ping doesn't work, does it return the IP address of the machine you are pinging, and then timing out, or does it just return "could not find host"?

I think name resolution is actually working.  Is Windows Firewall blocking your incoming and/or outgoing ICMP?

Please consider marking as "helpful", if you find this post useful. Thanks!... IT Guy since 12/2000... Virtual since 10/2006... VCAP-DCA #2222
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Josh26
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VMware's routing table has absolutely no involvement in the VM's routing table.

Can you do an ipconfig /all from both servers?

EDIT: As per above advice. Please disable Windows Firewall on both servers, reboot them and advise. Short name resolution can be done using broadcasts that silly Windows Firewall gets in the way.

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0x4C
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There's only 1 VM (the other VM I mentioned is a clients VM which is exhibiting the same issue).


Here's the ipconfig /all result:

Screen Shot 2013-03-07 at 22.08.51.png

Here's a copy of the ping FROM the server trying to ping itself via shortname:

Screen Shot 2013-03-07 at 22.11.25.png

Same server pinging itself via FQDN (::1: is a IPV6 address and apparently is normal for server 2008 to return according to a Microsofft KB I've read):

Screen Shot 2013-03-07 at 22.13.22.png

Lastly nslookup of the server:

Screen Shot 2013-03-07 at 22.14.48.png


Also thanks for the help gents Smiley Happy This is much appriciated.

Dave

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Josh26
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0x4C wrote:

Here's a copy of the ping FROM the server trying to ping itself via shortname:

26956_26956.pngScreen Shot 2013-03-07 at 22.11.25.png

Dave

This is the magical screen shot Smiley Happy

The ping command is interpreting your hostname, 0x3c, as a hexadecimal number, and deciding that you want to ping 0.0.0.60. This isn't remotely valid, so ping generates an unknown error.

It's highly recommended that a Windows Server name starts with a letter, and you've found one of the strange bugs regarding why.

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0x4C
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Hmmm... I'll do a reinstall and try a different name (Trust me to find the ONE obscure bug!)

This however doesn't explain the issue with my clients server which is named oz-dc-01 and is exhibiting the same behaviour.

Dave

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Josh26
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0x4C wrote:

Hmmm... I'll do a reinstall and try a different name (Trust me to find the ONE obscure bug!)

This however doesn't explain the issue with my clients server which is named oz-dc-01 and is exhibiting the same behaviour.

Dave

You should be able to simply rename the server.

Please get the same screenshots from your client's server, I doubt it would be exactly the same behaviour. The hex values do line up with the IP you are pinging after all.

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0x4C
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Well that did work! I did a reinstall as I'd messed with so many things I wanted a fresh install.

I am going in tomorrow to see the client I mentioned so i will get screenshots there.


Thanks for your help Josh!


Dave

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