In the last week or so, I've been getting complaints from customers who say
that they have problems accessing the Internet via their web browsers, ie;
page not found on a sporadic basis.
On investigation, I found that the problem is that their machines, either
(so far) WinXP or Win98 have the wrong DNS settings, namely the DNS server
is set to the gateway (LAN) address! All these systems are attached to
routers of various flavors, Linksys, Dlink, Orinoco, etc, which invariably
have the correct DNS server settings on it, DHCP is on and work (for
assigning IPs anyway), but go to the workstations and the DNS server (only
one) is always set to the gateway IP. A mix of bridged customers (with
their routers managed by us) and NATed (using SR-4000) are having this
problem.
The really odd thing is that sometimes having the DNS server set to the
gateway IP seems to work (perhaps because of some DNS caching in the OS?)
for some domain names. Others fail, I'm told. (I haven't been able to see
this in person...but I've talked enough people through it to get a good idea
of what's happening.)
Our DNS servers are primary; a Mikrotik router using DNS cacheing (which
also happens to be our border router), and then a secondary DNS server
provided by an upstream provider. This setup has been running without
issue for a year and a half. I've done no updates to the Mikrotik software
in probably 6 months.
Only fix I've been able to get to work is to have the customers hard set the
DNS to the correct servers on their machine's connection.
Reprogramming/rebooting the routers doesn't fix it---anyway it's a variety
of routers effected. Not everyone seems to be effected (yet), but I'm
getting a steady stream of complaints.
Anyone else seen this problem? And what in the heck could cause it???
Norm
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