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rishikesh.menon avatar image
rishikesh.menon asked mnakamura commented

How to specify DHCP Sub Options for Option 82 Config?

Hi Team, Is there any way to specify DHCP Sub Options under Option 82 config? I tried specifying it under DHCP option 82 as multiple option entries ,however no way it can define as sub-options. In PCAP I see error message as "Suboption 173: no room left in option for suboption value" Kindly advice if it can be possible. Regards, rishimenon
Spirent TestCenter (STC)dhcp
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rishikesh.menon avatar image rishikesh.menon commented ·
![alt text][1] [1]: /storage/temp/4104-sub+options.png Attached are the PCAP from customer based on which needs to be configured on STC DHCP option 82 config. Kindly review and advice. regards, Rishimenon.
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sub options.png (25.1 KiB)
sreerag.parameswaran avatar image sreerag.parameswaran ♦ commented ·
Rishi, please attach the actual PCAP file, I see only a screenshot. Thanks, Sreerag
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rishikesh.menon avatar image rishikesh.menon commented ·
.PCAP is not supported for file attachments. However for this query the option requirements are captured as a JPEG and attached. Regards, rishimenon
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rishikesh.menon avatar image rishikesh.menon commented ·
[link text][1] [1]: /storage/temp/4105-dhcp+renewal+wireshark.rar Hi All, Attached the .Pcap as a compressed file. Kindly review and advice. Regards, rishimenon.
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1 Answer

mnakamura avatar image
mnakamura answered mnakamura commented
Seems like you are asking two questions. How to add suboptions under option 82? Why is there a message "No room left in option for Enterprise data"? For the first question, it seems from the snap shot you were able to add a suboption under option 82. Did you use the Custom Option feature? If yes then, you can continue to add to that suboption. It is a matter of adding TLVs in a long string of Bytes. Example: I added Custom Option Value 82 and my Option Payload 01225441353030302d4d4731362d31333220504f4e20312f312f312f313a31302e312e310921000002980641445452414e000002990641445452414e0000029a0641445452414e` This long string actually has suboption 01 (Circuit ID) and 09 (Vendor Specific). It also has multiple Enterprise numbers under the Vendor Specific suboption 09. Just have to keep building in TLV format. For the second question, that just appears to be a wireshark decode issue. I also had wireshark 1.8.4 on my PC and that message does not show up.
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