Post by Grant MasonWe have a 2Mb ADSL connection with a /14 IP allocation. Our primary MX
record points to one of these. The other two MX records are Easynet's mail
servers.
You have a /28 in fact. You may have been confused by the RIPE route
object:
route: 217.204.0.0/14
descr: Easynet UK
origin: AS4589
mnt-by: EASYNET-UK-MNT
changed: ***@easynet.net 20010903
source: RIPE
However, only a small subnet of those IP addresses are allocated to
yourselves.
Post by Grant MasonIf we turn up for work one morning and find a pile of glowing embers where
the office used to be, what would our options be to continue receiving mail?
I guess we could amend the DNS records but that'll take time to percolate
around - we receive around 500 or so emails a day and we'd rather not miss
any.
If the IP address of the new mail server were an IP address on the
easynet network, this would be extremely simple. We would amend the
DNS zone file for your domain accordingly, and since the two backup
store and forward MX machines query local (to easynet) DNS servers,
those backup store and forward machines would almost instantaneously
discover the correct "new" highest priority MX. Global propagation
would not be an issue since sending external MTAs would first attempt
to deliver to the old highest priority MX, would not be able to and so
then would deliver to one of the two backup store and forward machines,
which would then deliver the mail to the new highest priority MX
machine correctly.
Another option of course would be arrange for all mail for the
domain to be routed to an easynet POP3 mailbox temporarily, which
again could be arranged extremely quickly and would not be affected
(as per the explanation above) by global DNS propagation (a switch the
other way around would though, so when switching back, there would in
all probability be a period of up to 48 hours where mail was being
delivered to the POP3 mailbox and also to your own SMTP server, so
you would need to take that into account when going back to the old
premises and/or DSL solution - however, no mail would be lost).
Post by Grant MasonIs there a way we could dial-in (ISDN, v.90, whatever) and be assigned with
the relevant IP of our MX record?
Essentially, no but it would not be necessary as we can provide either
of the two options referenced above. LLU DSL customers incidentally
are in a slighly different situation, since in the case of LLU DSL
customers we offer an option of ISDN backup with the same IP range
(as that allocated to the DSL solution) allocated to the backup
ISDN component; an LLU DSL customer who has purchased ISDN backup
who is concerned about disaster recovery can purchase a spare router,
pre-configured and ready to go so once the disaster recovery site goes
live, the router can be plugged in and used with its ISDN component
(it is a good idea to ensure that the spare router is kept off-site
though, for obvious reasons).
--
Anthony Edwards
easynet Ltd - Manchester
http://www.uk.easynet.net
***@uk.easynet.net