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

Peter Beckman beckman at
Wed Jun 18 15:44:02 UTC 2014

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

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

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: 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 at / +1-805-616-2471

Peter Beckman                                                  Internet Guy
beckman at                       

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