Slow page load (IPv6) with Internet Explorer 11

Recently, I found a website which loads very slowly in Internet Explorer 11 (under Windows 7) while other browsers did not affected (Chrome, Firefox). The site has both IPv6 and IPv4 addresses. Tcpdump showed that connection to the IP address is failed, Destination unreachable ICMPv6 messages returned in reply to SYN packets.

Despite the address is unreachable the operating system retransmists the SYN packets in a 9 seconds interval. There was a 12 seconds silence, and after a total waiting of 21 seconds the browser switched to the IPv4 address then the connection established under 2 milliseconds. Google Chrome behaves differently: after 300 milliseconds of the first failed IPv6 SYN attempt it immediately switched to IPv4 which is cannot be noticeable by the user. No annoying waiting, no unnecessary retransmissions.

An hour surfing on the net did not reveal any valid explanation. Interestingly, Internet Explorer 9 suffers from the same phenomena. I suppose this is by desing albeit very frustrating.

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Delphi compile timestamp

It could be useful to know the build date of the executable. In most situations this is the file’s timestamp.
It is quite simple to read it out in TDateTime format:

ExeDate := FileDateToDateTime(FileAge(ParamStr(0)));

However, there are situations when the file’s timestamp is altered and the build date is lost.

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