Re: Client on OS X, Browsers ALL fail DNS Lookup off net Hosts, SMTP+shell OK

[Peter Beckman <beckman () angryox com>]

1. It could be that DNS is working fine but port 80/443 is blocked or filtered
   when you leave the local LAN. New Firewall? Proxy authentication
   required?

2. The DNS server (cat /etc/resolv.conf) that the Mac hosts are pointed to
    can resolve internal but cannot reach external DNS hosts due to the
    upstream blocking DNS due to DNS amplification attacks (or bonehead
    admin).

3. Your resolver has a static configuration pointed to an upstream DNS
    server, and it has stopped responding and no backups are available.

4. Your resolver has a static configuration pointed to an upstream DNS
    server, and the primary DNS upstream server is offline and you aren't
    waiting 60 seconds for it to fail to the next DNS server.

That's my off-the-cuff assessment.

On Wed, 18 Jun 2014, Everett F Batey II Gi wrote:

> Newly evolved problems
>   (network has been good for years, no recent known upgrades, config changes):
>   Clients on MAC OS X,
>   Browsers ALL (FFox, Opera, Safari, Chrome) fail DNS Lookups for non-local web servers,
>   BUT:   SMTP mail, POP, IMAP and shell commands (ping, trace route) fully OK
>   AND:  www.google.com and a very few .orgs resolve on web browsers.
>   Connected via TWBC:  RCWE, 13820 Sunrise Valley Drive, Herndon, Allocations for this OrgID serve Road Runner 
> commercial customers out of the Honolulu, HI, Kansas City, KS, Orange, CA and San Diego, CA RDCs.  (Probably Orange Co, 
> CA)
>   No, MAC has no nsswitch.conf .. to there.
>      MAC HACKED (  )    DNS HACKED (  )  ISP FAILED fwdg DNS (  )
>       OTHER IDEA,  START POINT ____    Thnx
>
> —
>  VR, Ev / efbatey () gmail com / +1-805-616-2471

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Peter Beckman                                                  Internet Guy
beckman () angryox com                                 http://www.angryox.com/
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