"If-Modified", "Last-Modified" header

is it vital to a website's success?

[JoeHouse]

Hello

Recently I discovered my host server configuration does not include a "If-Modified", "Last-Modified" header.

There has been much bickering between my webmaster/programmer and seo people as to the importance of the "If-Modified Since" configuration.

I would like to clear up once and for all, is this configuration setup vital to a website's success?

I have been told if you make changes to your homepage daily even without this configuration you will still get spidered daily because of the intelligence of todays spiders/bots.

Is this true?

Have there been websites configured without this configuration and still did well in regards to traffic and spider visits etc.....?

Since my host's server configuration is not set up with this way, what should I do? Should I change host?

When I approached him on it he claims he never set one up like that and does not know how to configure it. Can anyone help? What advise would you give me?

I thank you in advance for your reponse.

[Tourz]

Hi Joe,

Its probably pretty important... check out the Google webmaster guidelines:

"Make sure your web server supports the If-Modified-Since HTTP header. This feature allows your web server to tell Google whether your content has changed since we last crawled your site. Supporting this feature saves you bandwidth and overhead. "

See [google.ca...]

I'd get a better host... they should know everything instantly :)

[JoeHouse]

Anybody else have any opinions on this subject?

[Dijkgraaf]

Having it enabled won't add to your success, it will however reduce your bandwidth cost, although many bots don't always send If-Modified-Since in the requests.

[physics]

Based on some things I've been seeing in my logs I think that Googlebot is requesting If-Modified-Since headers but don't take that as gospel...
<edited sending->requesting>

[edited by: physics at 8:04 pm (utc) on June 28, 2005]

[JKMitchell]

Never seen any evidence that bots use this - in fact I rank fairly highly for specific terms on my site and am happy with the results 1 of 1.83 million for a 5 word term, 5 of 1.3 million for a 2 word term and so on

My servers are not configured to send these headers.

If you really want to send them can you not do so using PHP (for example)?

[Dijkgraaf]

I've seen Googlebot and Yahoo's Slurp get 304 responses sometimes for .htm(l) files, so it must be sending If-Modified-Since. I've also tried putting cache control into some of my PHP pages, I've got it working correctly for browsers, however it doesn't seem to be working with those bots, so either I haven't got it quite correct, or they don't send If-Modified-Since for PHP pages. Has anyone got cache control working with PHP?

[bill]

Here's a flashback to the original GoogleGuy request for webmasters to use the If Modified Since header:

Are you using If Modified Since? [webmasterworld.com] You should be!

[Dijkgraaf]

Yes, I did see that thread, and I've tried implementing the If-Last-Modified since checking in PHP pages, however it doesn't appear to work for Googlebot, it works fine with browsers and at least one other bot.