суббота, 16 апреля 2011 г.

ns-2 network simulator installation on Ubuntu 10.10

Today I was required to install ns-2 from scratch in Ubuntu 10.10.
For this purpose it is needed to download archive from official site, extract it and run ./install in it's directory.
Before that build-essentials package is required to be installed via
apt-get install build-essentials.
After build-essential is installed, you can run ./install. This script will give you the error about undefined reference to `__stack_chk_fail_local' in otcl.c. How can you fix it? Simplest way:
disable stack protection: set the CFLAGS to -fno-stack-protector
For this purpose you can modify "install" on line 497 and set

        ./configure CFLAGS=-fno-stack-protector || die "otcl-$OTCLVER configuration failed! Exiting ...";
instead of
        ./configure || die "otcl-$OTCLVER configuration failed! Exiting ...";
 








пятница, 1 апреля 2011 г.

Do you know what...

- Default ARP entry timeout is 4 hours in IOS!
- DHCP Offer can be sent to all ones broadcast address instead of unicast address in certain situations.
- You can policy route route locally generated broadcast and multicast traffic with "ip local policy". For example this can lead to problems with dhcp server responses  to broadcast address.
- You can't use "match interface" in "ip local policy route-map"
- 255 is inaccessible administrative distance in IOS, you can use it for route filtering
- RIP doesn't generates corresponding Null0 routes for summary addresses opposit to EIGRP and OSPF. This can lead to different interesting situations like routing loops.
- You can't make as-path repend for IBGP routes
- "ip split-horizon" is disabled by default on frame-relay physical interfaces