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virgo0880

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DNS entry getting deleted for RHEL 6.0 from DNS server

Hi All,

I am getting a weird problem. I have a machine which is dual-boot RHEL6 and windows. When  it boots into windows I am able to ping and nslookup to its hostname and also I see the DNS entry for it in the DNS server.  But when I boot that machine in Linux, ping and nslookup to that machine stops working and suddenly there is no entry in DNS for this host. DNS server is the windows server. This machine gets its IP from DHCP.  Have anybody faced this issue earlies, whether RHEL 6.0 is removing the entry from the DNS. Need your expert help on this.

Thanks
virgo
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sfossupport
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You are using ddns which is mainly supported in windows. Since its a dual boot machine why
not use a static ip and do not use the computer to update the forward and reverse logs.
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virgo0880

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I did not understand your solution. You mean to say that I need to give static IP to linux machine instead of DHCP?  what is the problem with DHCP on RHEL 6.0, whether ddns is not supported on RHEL?

can you explain this statement please:

"do not use the computer to update the forward and reverse logs."
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sfossupport
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Ok, I will put that option in the configuration file and see if the problem goes away. Thanks.
whether the servername in DHCP_HOSTNAME should be hostname.domain.com or just the hostname?
Just put the hostname in and see if it shows up in your dhcp leases.
I tried adding that option, but still the same issue. Can't ping or do nslookup for the host. Following are the entries in ifcfg-eth0. Do you see any other issue here?


DEVICE="eth0"
NM_CONTROLLED="yes"
ONBOOT=yes
TYPE=Ethernet
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="System eth0"
UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03
HWADDR=BC:30:5B:B9:2D:C8
PEERDNS=yes
PEERROUTES=yes
DHCP_HOSTNAME="itdev-126"
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you need to use the long name

beware that your windows server may not publish that machine's name even if you got the proper configuration. it may choose to only publish the names of machines that are joined to the domain, for example, and may not like you impersonating a machine in the domain if you did not join it.

also note that if you choose to join the domain, you should use different hostnames for the windows and linux machines
what do you mean by "long name", are you saying the full FQDN name. If that is the case I have already tried that but still the same issue.

So as per your last statement whether I have to have 2 different hostnames to let the linux OS join the domain. In that case, we will have 2 hostname entries for the same IP address which I think can be a problem?

let me know what are your suggestions?

Thanks
yes i meant the fqdn, and even the fqdn with a dot at the end.

your installs are not the same machine. they have different ids and likes. i am not sure if it works, but i'm sure it's a bad idea to share the same machine accounts. anyway it is useless at best since they do not provide the same functionalities.

the entries only last as long as the dhcp lease lasts so sharing ips among machines is not a problem. after all, that's what dhcp and dynamic dns are about. the new entries will simply override the older ones. also note that there is no reason why both machines will get the same ip. you can make it liklier that they get different ones by using different mac adresses but that is not required.

i guess the next step would be to actually join the domain and see if that helps.

you also should be able either to sniff the dhcp session or look at the dhcp lease on your server in order to check that the hostname was actually passed over. at least we'll know if we need to look on the client or on the server side
So to join the system to the windows AD domain, whether I will need to install samba? Can you help me in providing the procedure of checking the dhcp server whether it is getting the hostname or not?

Thanks
to join the domain if that is what you want, yes you need samba.
the command shoud be "net ads join" if i remember properly

to see if the server sends what you want, you can install wireshark on either of the boxes and look at the dhcp packets. wireshark will decode them in human readable form. use a capture string such as "port 68" if you want to capture dhcp traffic. you may also be able to find that same information in the management console of the dhcp server by opening the properties of the machine. check if you see the host's name somewhere.
After doing more research on this, I found that RHEL6 have some bugs with updating the DDNS records with DHCP configuration. When RHEL6 gets IP from DHCP, it does not updates the hostname in DDNS due to which I was not able to ping and do the nslookups when the machine was booting in RHEL6. Even the option "DHCP_SERVERNAME" doesn't works in RHEL6.

So, I resolved the issue, by configuring the static IP in RHEL6. Now when the system boots in RHEL, it pings and nslookup also works. Giving points.
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