Enter network password, Firewall authentication

After putting on cume 4077 (M*A*S*H) on a V5R2 machine (and several other 
ptf's) when we try to access that domino server via a web browser by 
http://mydominoservername/mail/Postmast.nsf?OpenDatabase&Login 
I get the usual Notes user id and password screen.
Then another screen pops up that looks like the following:
Blue title bar = Enter Network Password
Firewall:  mydominoservername/it's ip address
Realm:  /mail
Scheme:  basic
User name
Password
I enter in my Notes user id and password (which doesn't match my NT or 
iSeries account in anyway), click on yes and get reprompted.
Again I enter in my Notes userid and password, click on yes, and it works.

Cisco kid says that is not coming from him.  There is no firewall in 
between my PC and that Domino server.  Routers and/or switches yes, but no 
firewall.

IBM/Lotus workaround is to insist on saying I did something with my 
firewall and to go in to my server document, Internet Protocols, Domino 
Web Engine, HTTP sessions and change Session Authentication from Disabled 
to Single Server.  That stops the prompt.

Two things:

1)  Sound familiar to anyone else?
2)  Any ramifications in changing Session Authentication from Disabled to 
Single Server?

Rob Berendt
-- 
Group Dekko Services, LLC
Dept 01.073
PO Box 2000
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com