barrett@Daisy.EE.UND.AC.ZA (Alan P Barrett) (06/21/91)
Neil Rickert suggests the following as a method of changing the SOA serial number from yyyymmddnn format to yymmddn format: > Start by using: > 4199106150 > (i.e. with a superfluous leading 4). > > Use this format for a week, or so, till you are sure all outdate copies > of your SOA record have timed out everywhere. Then drop the leading '4'. In 32-bit sequence space arithmetic, 4199106150 compares as *less* than 1991061500 (since the difference between them is larger than 2^31), so the details of Neil's suggestion aren't quite right. If you want to make the change in two steps, the serial number at the middle step would have to be reasonable carefully chosen to avoid exceeding the maximum permitted rate of change[*] (for example, 1991mmddnn --> 32000mmddn --> 1991mmddn would be OK). I would wait for the full length of the zone expire period between changes, because that is the only way I know of being absolutely certain that the secondary nameservers have expired the old copy of the zone. On the other hand, if you don't mind breaking the rules, and if you are on good terms with the folk who run all your secondary nameservers, you could probably just change from yymmddnn to yymmddn in one step, and ask all the secondaries to force a manual reload at some prearranged time. --apb Alan Barrett, Dept. of Electronic Eng., Univ. of Natal, Durban, South Africa RFC822: barrett@ee.und.ac.za Bang: m2xenix!quagga!undeed!barrett [*] Although the RFCs don't say this in so many words, my reading of RFC1034 and RFC1035 implies that the serial number must never be incremented through half or more than half of the available 32-bit space during any time period whose duration is less than or equal to the zone expire period which was in effect at the start of the time period. For example, if right now you have serial number 1991061501 and an expire period of 3 months, then three months from now the serial number must still be less than 41388545149 (which is 2^31 more than the current serial number).