I have a Red Hat Linux 6.1 server functioning nicely doing IP
masquerading for my home network of Windows PCs. I can use it to dial
out using ppp to the network at work and ping, ftp, http and telnet to my
hearts content. My ipchains rules are the basic:
ipchains -P forward DENY
ipchains -A forward -j MASQ -s 192.168.1.0/24
Unfortunately the e-mail servers at work are Exchange servers and they
only support Exchange and Outlook clients. No POP3 and no IMAP. So I
need to run an Exchange client. Currently I have to shutdown the Linux
ppp link, futz around with cables and dial out from a PC to get a
connection that lets my Exchange client work.
A couple of days ago someone posted a simlar problem and the given
solution was to add:
ipmasqdm -portfw -a -P tcp -L "External NIC" 25 -R "Mail Server
Apparently that worked because there hasn't been any further traffic on
the issue :-)
Unfortunately RH 6.1 doesn't seem to have anything called "ipmasqadm".
I fired up tcpdump on the ppp0 interface and watched lots of interesting
traffic go by (I captured it too) as I tried to start up exchange but I'm
afraid that it was all over my head -- I'm not sure how to apply any of
that to ipchains in order to get exchange to work.
Does anyone have a simple solution for RH 6.1 that will allow me to use
exchange without dedicating a PC and a modem to the effort?
Alternatively -- what process can I follow to figure it out myself? I'm
assuming that I can use tcpdump to analyze the traffic and bit by bit
through trial and error determine what I need to do. But I may be old
and gray by the time that I figure all that out...