ssh scary warning!

I recently leased a second linode and redirected the ip address for a domain previously mapped to linode1 now to linode2. This new linode has 2 ip addresses. One is mapped to host.domain.tld, the other is mapped to domain.tld. I use zone edit to map the ip addresses to hostnames and have configured reverse dns on the linode accordingly.

when I execute

$ssh host.domain.tld

the connection is made and no errors are given

however, when I execute

$ssh domain.tld

the connection is made and I get the following output

'Address pdq.z.y.x maps to host.domain.tld, but this does not map back to the address - POSSIBLE BREAKIN ATTEMPT!'

any ideas on what I've done wrong? I've waited the requisite hour for dns to update but still see this error.


3 Replies

I think RDNS updates take longer - maybe 24 hours?

All seems to be working now and I've made no changes since I last saw the problem (about 8 hours ago)?

Yeah, that was just a DNS propagation issue. It depends on what the TTL (time to live) is on the zones in question, and how long ago the DNS server cached it.

I host my own zones and can control the TTL etc… but obviously I don't have as much control over the reverse. Since I use my own DNS server as my resolver too, I can flush my own cache in these kinds of cases and see the changes immediately, regardless of previously cached TTL times. If you're not resolving off of your own server, and using a different one, then you're at it's mercy. :)


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