In looking through the dosbox.conf that comes with 0.63, i've noticed a section which reads as follows:

[modem] # modem -- Enable virtual modem emulation. # comport -- COM Port modem is connected to. # listenport -- TCP Port the mod […]
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[modem]
# modem -- Enable virtual modem emulation.
# comport -- COM Port modem is connected to.
# listenport -- TCP Port the modem listens on for incoming connections.

modem=false
comport=2
listenport=23

Does this area of dosbox work? If so, How do I define an IP address to connect to? does this happen on dial? Is there an emulated/fake AT command set for this? Documentation seems to be scarce on this.