For about 2 weeks, multiple people (around 10 that I know of) in our company are having trouble accessing Stack Overflow; independently of the browser, and on Linux as well as Windows. The symptom is that assets loaded from cdn.sstatic.net
keep waiting forever or until they time out.
On my machine the status is that at some point those requests time out and a version of the page without any images or CSS appears.
For some Windows users reboots help, for others it doesn't.
Meta Stack Overflow (now Meta Stack Exchange) always loaded for me.
A workaround for my machine was to disable IPv6 temporarily on Linux with the command echo 1 | sudo tee /proc/sys/net/ipv6/conf/all/disable_ipv6
.
Note that no other site (that I visit) has been affected like this.
Update 2013-08-12: our network guy did some checking and insists the problem lies with Cloudflare. We seem to have issues when trying to connect to them with IPv6. We can't go around and disable our IPv6 Support since we need it for our internal infrastructure. We employ the following workaround (sadly only works with Firefox):
- Go to about:config
- find the configuration key called
network.dns.ipv4OnlyDomains
- Set it to the following list of domains (or add them if you already have something in this key):
cdn.sstatic.net,www.cloudflare.net,cdn-careers.sstatic.net
host -t AAAA cdn.sstatic.net
resolve okay? If not, does using Google's DNS help,host -t AAAA cdn.sstatic.net 8.8.8.8
? (Note that Meta does not use the CDN. Nice workaround!)nslookup -t=AAAA cdn.sstatic.net
andnslookup -t=AAAA cdn.sstatic.net 8.8.8.8
)host -t AAAA cdn.sstatic.net
seems to work fine, output: cdn.sstatic.net is an alias for sstatic.net.cdn.cloudflare.net. sstatic.net.cdn.cloudflare.net has IPv6 address 2400:cb00:2048:1::be5d:f43a sstatic.net.cdn.cloudflare.net has IPv6 address 2400:cb00:2048:1::be5d:f53a sstatic.net.cdn.cloudflare.net has IPv6 address 2400:cb00:2048:1::be5d:f63a sstatic.net.cdn.cloudflare.net has IPv6 address 2400:cb00:2048:1::be5d:f73a sstatic.net.cdn.cloudflare.net has IPv6 address 2400:cb00:2048:1::8d65:723b