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From Matus UHLAR - fantomas <uh...@fantomas.sk>
Subject Re: [users@httpd] Establishing a new connection sometimes takes long (30s).
Date Tue, 13 May 2008 21:18:09 GMT
> > > Why would this be a DNS issue? The problem happens on the SERVER

> > because the most common reason for this is DNS issue.

On 13.05.08 12:37, Alex Grässer wrote:
> Granted, but we have ruled that out by putting the names into the hosts.

using local caching DNS is usually much more effective. Aren't some IPs
missing in the hosts file? e.g. dnsmasq can read hosts file and provide its
content via DNS. But if some hosts are missing, it may sometimes delay the
resolution, and sometimes just cache negative answer (host not found).

> file. What is strange is, that this does not happen every time a new
> connection is made. When requesting the same page continuously, the
> connection gets disconnected after the 100th call. As it should because of
> the KeepAliveRequests setting. When the client reconnects, it sometimes is
> near instantaneous and sometimes takes up 30seconds. The times vary from
> 35ms to 30seconds.

> > > and HostnameLookups is Off!
> 
> > isn't it turned on somewhere?
> 
> The HostnameLookups setting is global. I have not tried to put it into
> each VirtualHost. But if it were turned on would you not see the resolved
> host names in the access.log?

Not, if they are not resolved, e/g/ if the resolving times out (which is
exactly what causes the delay in such cases)

> > another reason might be an IDENT being required... 
> 
> This is a straightforward HTTP GET request. I don't think IDENT is a
> problem here.

if you configured apache to get IDENT response from connecting user, the
server tries to get response by every connection made, which may sometimes
fail, sometimes not.

> > > Does Apache count (reverse) DNS lookups towards the execution time?
> 
> > I guess so. 
> 
> Then you should see the time in the access.log, which we are not.

The lookups may be once fast, once slow... or "usually fast, sometimes slow"
which would explain your problem. I'm not telling you that it's the problem,
just explaining that it might be it.

-- 
Matus UHLAR - fantomas, uhlar@fantomas.sk ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
"To Boot or not to Boot, that's the question." [WD1270 Caviar]

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