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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical RE: How not to make an error page (was: OT: www.Amazon.com down?)
The actual headers returned are: Server: NS_6.1 Content-Length: 62 Connection: close 503 Service Unavailable Fred Reimer, CISSP, CCNP, CQS-VPN, CQS-ISS Senior Network Engineer Coleman Technologies, Inc. 954-298-1697 -----Original Message----- From: Bjorn Townsend [mailto:[email protected]] Sent: Friday, June 06, 2008 2:58 PM To: Andy Litzinger Cc: [email protected] Subject: Re: How not to make an error page (was: OT: www.Amazon.com down?) Good guess. AFAIK Amazon uses mostly Netscaler, with some homegrown stuff and a few F5 boxes. On Fri, Jun 6, 2008 at 11:49 AM, Andy Litzinger <[email protected]> wrote: > I've no idea what Amazon uses for Load Balancers, but I'm pretty sure > that error message is the default error message served up by a Netscaler > LB if no web services are available in the pool... > > -andy > >> -----Original Message----- >> From: Kevin Day [mailto:[email protected]] >> Sent: Friday, June 06, 2008 11:40 AM >> To: Lasher, Donn >> Cc: [email protected] >> Subject: How not to make an error page (was: OT: www.Amazon.com down?) >> >> >> On Jun 6, 2008, at 1:24 PM, Lasher, Donn wrote: >> >> > Checked, and doublechecked, not just me >> > >> > www.amazon.com returns: >> > >> > Http/1.1 Service Unavailable >> > >> > Anyone have a URL for a network/etc status page, or info on the >> > outage? >> > Been that way for a while this morning. >> > >> > -donn >> > >> > >> >> Even worse, the page they're displaying is actually a HTTP 200 >> response code(OK/no error), with no "Don't cache this" header - which >> means their error page is considered cacheable by some browsers/ >> proxies. So, you may find users who tried to visit Amazon while they >> were down are still seeing it down long after they fix it. >> >> Lesson to high profile websites: add these to your error pages so you >> don't have people complaining you're still down long after you're >> fixed. >> >> * Don't return a 200 response code. Use 500 or 503. Nothing from 2xx >> or 4xx. >> * Add a "Cache-control: no-cache, must-revalidate, max-age=0" header, >> as well as an "Expires: 0" header for good measure. >> * If your server is really borked and you can't add headers at all, >> add '<META HTTP-EQUIV="Pragma" CONTENT="no-cache">' to the <head> >> section. That's not as good, but helps at least on the browser end. >> * If possible, add a timestamp to the page somewhere (even if it's in >> an HTML comment) so you can troubleshoot with users still seeing the >> error. >> >> -- Kevin >> > > > -- Bjorn Townsend | [email protected]
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