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DHCP eMTA Provision of Cable Modem Option 12 Option 122

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Posts: 2
2023     0

Hello, we're on the tail end of a large DHCP migration from the old Solaris ISC DHCP servers to InfoBlox.  The last customer to migrate has cable MTAs and this part was not taken into consideration by the person migrating initially.  We're now trying to get eMTA cable modems to successfully provision within Infoblox. We were able to get the  DHCP Option 122 work around string from Infoblox. When we tested we were able to get close but not completely provision an eMTA modem. We got Telephone1,Telephone 2 lights, but received only a fast busy signal. The cable modem logs indicate there was some sort of hostname or FQDN issue. The old ISC DHCP server produced mtamacaddress.mta.domainname.com and since we switched to infoblox we see dhcp-10-x-x-x.mta.domainname.com with the “Generate Hostname if not sent by Client” box being checked..

 

The first step the tech takes is to get the modem online by assigning it to a profile in our custom provisioning software. When modem is online they go into an application called Metaview where they specify the hostname as such ex. mtamacaddress.mta.domainname.com.

 

I think we've overlooked adding something to Infoblox that will make this work correctly. I believe this could have something to do with the host-name(12) string needing to be added; as we do not have it listed for cm or mta in infoblox but is defined on the old DHCP server.  If that is indeed a requirement, how should it be specified?  On the Old DHCP server there is a large block as follows:

 

option host-name = concat ("mta",suffix (concat ("0", binary-to-ascii (16, 8, "", substring (hardware, 1, 1))),2), "", suffix (concat ("0", binary-to-ascii (16, 8, "", substring (hardware,2, 1))),2), "", suffix (concat ("0", binary-
to-ascii (16, 8, "", substring (hardware, 3, 1))),2), "", suffix (concat ("0", binary-to-ascii (16, 8, "", substring (hardware, 4, 1))),2), "", suffix ( concat ("0", binary-to-ascii (16, 8, "", substring (hardware, 5, 1))),2), "", suf
fix (concat ("0", binary-to-ascii (16, 8, "", substring (hardware, 6, 1))),2));
ddns-updates on;
ddns-domainname "mta.domainname.com";
ddns-hostname = concat ("mta",suffix (concat ("0", binary-to-ascii (16, 8, "", substring (hardware, 1, 1))),2), "", suffix (concat ("0", binary-to-ascii (16, 8, "", substring (hardware, 2, 1))),2), "", suffix (concat ("0", binary-t
o-ascii (16, 8, "", substring (hardware, 3, 1))),2), "", suffix (concat ("0", binary-to-ascii (16, 8, "", substring (hardware, 4, 1))),2), "", suffix (concat ("0", binary-to-ascii (16, 8, "", substring (hardware, 5, 1))),2), "", suffi
x (concat ("0", binary-to-ascii (16, 8, "", substring (hardware, 6, 1))),2));

 

Can that be converted to the host-name(12) in infoblox?  I suspect not as the person setting this up would have done so I believe.   Are there any suggestions or pointers of what's missing?  Thanks for any help you can offer.

Re: DHCP eMTA Provision of Cable Modem Option 12 Option 122

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Moderator
Posts: 149
2023     0

That conf means that Solaris is crafting hostnames (option 12) for clients based on hardware info (MAC) shared during lease transaction. Looks like it is adding "mta" to the beginning, followed by concatenating the six octets in the MAC address, perhaps without the colons.

Unfortuantely I cannot immediately think of a way to configure this in Infoblox via GUI but I'll keep you posted if I find anything beneficial. If you've already found the trick, please let me know.


Best Regards,
Bibin Thomas

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