Re: [nznog] Bitstream 3a DHCP manipulation

Hi Jed No, in this situation the clients are at the UNI end. The dhcp server is off a switch of ours very close to the UFB SP handover. When I get back to work tomorrow I'd be happy to share a limited amount of the pcap. Just have to be careful as we were capturing everything on a particular interface. Would a filtered pcap just showing DHCP packets suffice? Cheers Dave On Thu, Apr 3, 2014 at 6:46 PM, Jed Laundry wrote:

Hi Dave,

So this is with the DHCP server on the customer (UNI) end of the BS3?

I remember back a few years ago we hit some software bugs getting this working in the lab, and given it's an uncommon scenario (there's one (i think?) other provider using it atm) I wouldn't be surprised if there's more.

Would you mind sharing a pcap/diag off list?

Thanks, Jed.

Sent from a small screen. On 3/04/2014 4:52 pm, "Dave Mill" wrote:

...

Hi all

I posted a few weeks ago about MAC limits on Bitstream 3a connections. This is related to that. This is a UFF Bitstream 3a connection.

I've discovered that a customer's only complaint with a Bitstream 3a connection from us is that DHCP doesn't work over this. I've obtained some pcaps from both ends and I can see the following changes occurring to a DHCP Request:

1) The transaction ID is changed 2) Option 82 is added. More specifically, sub-option 1 Agent Circuit ID is present and has a valid length. sub-option 2 Agent Remote ID is present, has a length of 0 and no content which wireshark doesn't seem to like much.

I've had a brief read of RFC3046 and I can't really tell if its valid to have a sub-option with a length of 0 or not.

https://tools.ietf.org/html/rfc3046#page-8

I never see any DHCP ACKs coming back from the customer's DHCP server.

I've had a read of some of UFF's Bitstream3a docs and can't see any mention of DHCP. I can see in one of our initial requests we had to fill out we can choose to have DHCP Relay Agent Functionality but this seems to be related to Bitstream2 only and also this defaults to be disabled.

I don't know what DHCP server the customer is using right now but I hope to find this out soon.

Questions for anyone with more experience in this than myself: -Can changing the DHCP Request transaction ID cause issues? -Has anyone come across DHCP servers not liking option 82 being set, or not liking sub-option 2 having a 0 length? -Has anyone successfully used DHCP across a Bitstream3a connection? How about a UFF Bitstream3a connection? -Am I missing anything obvious?

Obviously I might end up talking to UFF over this but I just want to see what others on the list know before doing so.

Again, I don't really want to debate the wisdom of plugging two LANs in over a Bitstream3a connection.

Cheers Dave

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