On 6 Jul 2016, at 14:25, SH Development wrote:
Ah…and maybe the light bulb just clicked on.
Turns out the IP in question that is able to get through starts with
192 which is why it is the only one able to do this, maybe?
Yeah, sure, maybe. Probably. Maybe there's something else involved.
As Viktor suggested: Read Postfix's DEBUG_README, which is on the
website and probably is installed on your system as well. Its last part
describes how best to get useful help here by providing enough
information so we don't have to guess.
Also expanding on Viktor's message: 192/8 includes 192.168/16 (RFC1918
private space) and also 192.0.2/24 (TEST-NET) and probably other
special-use /24s I'm forgetting, but the bulk of 192/8 once carried a
charming nickname: "The Swamp". This was in part because that's where
early allocation of Class C space started and there are squishy issues
around which addresses in there are whose, but also because for years it
was full of a very large number of very small routes of dubious value.
It's a bad area to get sloppy with IP range specification because of its
extreme balkanization.
