[Greylist-users] Re: Socket timeouts

richard at stardate.ca richard at stardate.ca
Mon Aug 11 22:02:19 PDT 2003

> IIRC, on linux, the default /proc/sys/net/ipv4/tcp_syn_retries is 5, 
> and each takes about 30 seconds to time out,
> which is about 2 minutes and 30 seconds.

> This simple command;
> > time telnet
> will give you a very good idea what the socket connect 
> timeout is on your system.

> But if you're asking how long you should wait before closing
> an inbound connection, RFC 2821 has some specific recommendations,
> most of which are 5 minutes. 
> See RFC 2821 section Timeouts, for details.

Thanks, that is good info.

> If you're the one connecting, keep in mind that many servers 
> do an rDNS lookup these days, which can add as much as 3 minutes
> to any other connection delays.  (If you're doing one, 
> consider not doing it and just using the IP address.)

No. I want to have a privat SMTP for local users and a public greylisting
MX for the rest of the world.

It turns out that my problem was of my own making that I could not find 
for the life of me. I spent the weekend rewriting the SMTP. As an SMTP 
reciever (no grey listing) it is working perfectly.  I think coding SMTP
and grey listing at the same time was my downfall because it was to hard
to debug, especially when it is my first crack at writing an SMTP 
reciever.  What was realy buggering me up was that I could always send 
mail through and some remote servers could always push mail through while
most others failed constanly.  It turns out the SMTP was listening when 
it should have been sending.  I chose a rewrite because I would (did) end
up with cleaner, better and more debug friendly code.

Now I can incorperate the grey listing knowing any failures will be just
in the grey listing code additions.

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