Lots of help coming in here, for which I am eternally grateful. Thank
you all.
Chris,
Yeah, nope. I've scoured the maillog and there's no errors there.
IMAP Backend is local file based.
The conversation seems to have migrated to the mail server, but its not
just that. As mentioned HTTP calls through the box take their time
coming up too.
Martin,
thanks the detailed response.
Yes, James Polley pulled me on that earlier too. Sorry. A case of
mis-capitalisation (or dropped zeroes). I can never remember which is
which there. The modem is reporting a 15559Kbps/1219Kbps Down/Up
connection and I'm not more than 1Km from the exchange (So I suspect
Netcomm have it wrong too, because I read that as 15 Megabytes per
second). As mentioned Noise Margin: ~9dB, Attentuation: ~26dB. Modem
connects over PPPoA and I have set MTU to 1492 all the way through the
chain (LAN hosts, Linux eth1, eth0, Modem LAN, WAN).
I am with internode and the 10Meg test you offered lands literally in a
blip.
Keeping it simple with HTTP (using Firefox), a site like smh.com.au
(where I visit daily, so if there's any local caching going on, it's
cached and I reckon internode would likely be caching smh.com.au) takes
a minimum 11 secs to load and regularly 20+ secs. This is from behind
the linux box. However, if I attempt to load smh.com.au from the linux
box, it loads in 3secs flat. I don't have squid or any proxying server
running myself - at least not that I have personally configured.
Same token; Firefox on linux to load www.telegraaf.nl (a miscellaneous
EU website) 13.7secs. Firefox on an OSX MAC (4GB RAM) behind the linux
box (with only switch in between) 27+ secs before it got anywhere near 99%.
It just seems the Linux box is the bottleneck. Especially when if I
_first try to connect either with HTTP _or_ IMAP, I get timeouts. It's
like the box takes time to wake up from something.
Just to recap. The machine is all-in-one;
Postfix/Dovecot/Spamassasin/Amavisd/Clamav mail server.
DHCP, DNS server
LAN Router
Firewall
By all accounts memory seems to be working as it should and is not
overloaded.
CPU Load rarely goes above 30-40%
DHCP licences work and zones are updated with no errors
DNS calls from cli return almost instantaneously. nslookup some domain
in the EU which I happen to know exists and the server instance of
'named' comes back almost instantaneously with a response.
I can ping servers I know are located in the EU and get avg. 340ms
responses.
Relevant iptables rules look like;
# IMAP(S)
-A chain-IN -p tcp -m tcp --dport 993 -m state --state NEW -j ACCEPT
# HTTP(S)
-A chain-IN -m tcp -p tcp --dport 80 -m state --state NEW -j ACCEPT
-A chain-IN -m tcp -p tcp --dport 443 -m state --state NEW -j ACCEPT
The more I read from you good folk, the more inclined I am to believe I
have indeed done the right thing with the linux box and it "may" not be
the linux routing processes itself. But I've only the one Linksys SD-208
switch between linux and the rest of the network and all reviews I've
read about the linksys are good. It's run well for a number of years now.
------------------------------------------------------------------------
Kind Regards
Kyle
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