In message <20131102002035.963ba96d...@rock.dv.isc.org>, Mark Andrews writes: > > In message <52743027.7050...@necom830.hpcl.titech.ac.jp>, Masataka Ohta write > s: > > Mark Andrews wrote: > > > > >> It is a lot simpler and a lot more practical just to > > >> use shared secret between a CPE and a ISP's name server > > >> for TSIG generation. > > > > > > No it isn't. It requires a human to transfer the secret to the CPE > > > device or to register the secret with the ISP. > > > > Not necessarily. When the CPE is configured through DHCP (or > > PPP?), the ISP can send the secret. > > Which can be seen, in many cases, by other parties which is why I > discounted plain TSIG key exchanges over DHCP years ago regardless > of which side send the key material.
Now you could do a DH key exchange over DHCP then do a encrypted TSIG key exchange. This however also requires a encrypted key exchange of the TSIG with the nameserver. The DHCP server could do this with TKEY. Note a full DH key exhange is not strictly required. The CPE could just send a public key and the DHCP server could encrypt the TSIG secret using it when replying. > > > I'm talking about just building this into CPE devices and having it > > > just work with no human involvement. > > > > See above. > > > > Involving DNSSEC here is overkill and unnecessarily introduce > > vulnerabilities. > > You do realise that you can use KEY records without DNSSEC. The > KEY record is in the zone to be updated so it is implictly trusted. > > > Masataka Ohta > -- > Mark Andrews, ISC > 1 Seymour St., Dundas Valley, NSW 2117, Australia > PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org > -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org