Static v Dynamic IP on dial-up?

Riley Williams (rhw@bigfoot.com)
Tue, 20 Oct 1998 11:03:14 +0100 (GMT)


Hi Andi.

> That is true for dialup links with static addresses. But 99% of all
> dialup links have dynamically allocated addresses, where it is
> rather unlikely that you get the same address again. It could
> happen in theory, the probability depends on the particular setup.

I've used both static and dynamic dial-up, and noticed both advantages
and disadvantages to each. Here's my comments:

1. Having a dial-up with static IP means that one can only have one
link in use at a time, thus the EQL driver serves no purpose in
this situation. This can on occasion be a serious handicap.

I have been in the situation of advising a customer with static
IP addressing who had THREE 33k6 modems connected to their
internet gateway, and needed a rather large file rather faster
than a single modem link could deliver it. Unfortunately, their
static IP prevented using multiple parallel modem links to push
the bandwidth up enough to meet their deadline...

2. Having a dial-up with dynamic IP means that one generally gets a
different IP address assigned every time one connects, which can
cause some protocols to lose their channel over a disconnect and
reconnect sequence.

However, in my experience, this generally does NOT occur when IP
Masquerading is in use - although I've no idea why...

3. A dial-up with dynamic IP also has the advantage that if somebody
wants to hack into your system, they have the additional headache
of locating its current IP address before they can start - and if
one suspects one is being hacked into, it's a trivial exercise to
disconnect and reconnect, thus changing that IP address anyway.

Comments?

Best wishes from Riley.

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