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The Hebrew University of Jerusalem
Computation Authority
News bulletin #124
17-September-1998
Today's topics:
- Internet service interruptions due to IBM maintenance.
- Ping blocked due to flooding.
- News delays.
- Modems problems.
- Shana Tova.
o Internet service interruptions due to IBM maintenance: The following
message is from IBM who connects Machba's network to the worldwide
Internet:
On this coming Sunday morning, 20/09/98, the Israeli Electric Company
will be performing infrastructure maintenance work in IBM Israel. The
work will take place from 1:30AM till 6:30AM - Sunday morning. In
order to minimize the affect of the maintenance work on your
connectivity we have created a special UPS environment to handle a 5
hour power outage. Internet services will be interrupted at the
beginning of the maintenance window (1:30am) and once again at the end
of the maintenance window (around 6:30am). Each interruption will be
for approximately 15-20 minutes. We apologies for the inconvenience!
We wish you all a happy New Year and hope that your wishes will come
true.
o Ping blocked due to flooding: The following message is by curtesy of
Hank Nussbacher:
For the past 2 months, ICMP (aka ping) from ILAN (the Israeli Academic
Network) to the greater Internet has been blocked. The networks
blocked were the university networks starting with 132.x.x.x
addresses. Two days ago, this block was expanded to include the
128.139.x.x, 147.233.x.x, 192.114.x.x and 192.115.x.x address ranges.
The implication of this block is that you will not be able to use ping
in order to verify connectivity to international hosts. Machba has
been hit by consistent ICMP attacks from abroad over the past year.
This usually steals about half (if not more) of the available
bandwidth Machba has to abroad (this past Sunday morning - the attack
took out 1.8Mb of Machba bandwidth to abroad) and generally cause all
network services to slow down. It would appear that people abroad
have targeted Machba and due to the fact that spoofed IP addresses are
used - it is close to impossible to backtrack and determine who is
responsible for this every time it happens. The alternative is to
either learn to live with these attacks (and suffer from consistently
terrible response time - even for Business Class users) or to block
ICMP (which is used for ping). The blockage of ICMP in the USA and
Europe destined to Machba was decided upon in order to save the Machba
network from these attacks. Only selected Machba hosts will be
allowed to receive ICMP from abroad (generally used for network
monitoring purposes). If you have a certain system that requires ping
in order to function properly, please let me know and it will be added
to the exception list.
o News delays: During the past few weeks incoming news feed is stopped
around noon and resumes only at the next mornning. This is because
the volume of incoming news has been raised dramatically and our disks
are getting full; the news feed is stopped until the nightly process
clears it. We hope to solve this in the future with more disks.
o Modems problems: As you might have noticed lately our modems system
availability and performance has been decreased. We are aware of it
and are trying to find the budget to fix it (actually we are trying to
find it for 18 months already; probably it is not found since this
service is not important.
o Shana tova to all of you (at least I don't have to ask for a budget to
wish it to you...).
__Yehavi:
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