web pages not loading (from certain networks) but not a routi ng i ssue.

Fri Sep 7 15:00:32 UTC 2001

This reeks of an MTU problem somewhere.

Did you happen to have ICMP filtered to/from your sites recently? Remember, ICMP
isn't just that protocol that lets you ping stuff. You may have broken path MTU
discovery.

Jason Young
CNS - Network Design, Anheuser-Busch
(314)577-4597

> -----Original Message-----
> From: Nanog [mailto:Nanog at exchange.ware.net]
> Sent: Friday, September 07, 2001 9:52 AM
> To: nanog at merit.edu
> Subject: web pages not loading (from certain networks) but 
> not a routing
> i ssue.
> 
> 
> 
> Ok guys,
> 
> Interesting problem that seems to have started on Friday.
> 
> Here's the deal, it seems that certain (not all) web pages on 
> various sites
> we host are not loading for certain customers. It started on 
> Friday with
> visitors on Verizon DSL waiting forever for pages to load.
> 
> Yesterday and today PacBell DSL and some Netcom customers started
> complaining.
> 
> This only seems to occur on HTTP traffic. If we have the 
> visitors try HTTPS
> the pages load fine (with the normal encryption slowdown). 
> 
> We've looked at Layers 1-4, and can't see any problems, ping 
> looks great,
> interfaces and cpus on routers, servers and switches look fine.
> 
> It's almost like it's a transparent cache "bug". Anyone know 
> if Inktomi, or
> any major cache vendors rolled out any new code this week?
> 
> For that matter does anyone know what caches Verizon and SBC use for
> starters?
> 
> Other variables: it only seems to occur on IIS based systems 
> (I know I know,
> no flame wars or suggestions for replacements). Although it's 
> not happening
> on all of our IIS servers.
> 
> Any clues are greatly appreciated.
> 
> Steve
> 
> 