Re: [squid-users] timeout option needed for ipv6 even in squid-3.4.6?

...and just as an addendum, telnet shows the kind of behaviour I'd
expect to see from squid

telnet cs.co 80
Trying 2001:4800:13c1:10:222:19ff:fe00:cbb...
Trying 67.192.93.178...
Connected to cs.co.
Escape character is '^]'.

On 28/07/14 10:35, Jason Haar wrote:
> Hi there
>
> I'm seeing a reliability issue with squid-3.1.10 through 3.4.6 accessing
> ipv6 sites.
>
> The root cause is that the ipv6 "Internet" is still a lot less reliable
> than the ipv4 "Internet". Lots of sites seem to have a "flappy"
> relationship with ipv6 which is not reflected in their ipv4 realm. This
> of course has nothing to do with squid directly - but impacts it
>
> So the issue I'm seeing is going to some websites that have both ipv6
> and ipv4 addresses, ipv6 "working" (ie no immediate "no route" type
> errors), but when squid tries to connect to the ipv6 address first, it
> hangs so long on "down" sites that it times out and never gets around to
> trying the working ipv4 address. It also doesn't appear to remember the
> issue, so that it continues to be down (ie the ipv6 address that is down
> for a website isn't cached to stop squid going there again [for a
> timeframe])
>
> Shouldn't squid just treat all ipv6 and ipv4 addresses assigned to a DNS
> name in a "round robin" fashion, keeping track of which ones are
> working? (I think it already does that with ipv4, I guess it isn't with
> ipv6?). As per Subject line, I suspect squid needs a ipv6 timeout that
> is shorter than the overall timeout, so that it will fallback on ipv4?
>
> i.e. right now I can't get to http://cs.co/ as their ipv6 address is
> down, but their ipv4 address is up and working - but squid won't try it
> because it hangs so long trying the ipv6 address (and on the flip-side,
> www.google.com is working fine over ipv6). To put it another way,
> squid-3.1.10 and newer work fine if the ipv6 address allocated to a site
> is up and responding, but cause issues if it is not
>

-- 
Cheers
Jason Haar
Corporate Information Security Manager, Trimble Navigation Ltd.
Phone: +1 408 481 8171
PGP Fingerprint: 7A2E 0407 C9A6 CAF6 2B9F 8422 C063 5EBB FE1D 66D1