The IPv6 designers refused to define an IPv4/IPv6 gateway, because it’s a contradiction to the NO-NAT, End2End paradigm of IPv6. The result is that IPv6 doesn’t really lift off, because every IPv6 user has IPv4 too (Dual Stack), which gives no pressure to move on to implement IPv6. Large providers had to implement NAT instead […]
I had to update the software of a new Cisco Catalyst 4948 yesterday. As usual I did: copy tftp://<hostname>/<filename> bootflash: conf t boot system flash bootflash:<filename> exit reload But the switch ignored the new software image. During boot it said: Booting first image from bootflash Solution: The config-register was set to 0x2101 right out of
Update Cisco Catalyst Software Read More »
When I restart my Pirelli modem it allways disconnects all TCP connections! After the connection table of the Pirelli is flushed (by rebooting) it sends a RST for the next packet of any TCP connection.Why doesn’t it simply forward this packet. Client and servers don’t care if a router on the way is rebooting. Pirelli
Pirelli Modem does allways NAT Read More »
Problem: Pirelli modem is not transparently routing traffic for tcp port 7070 and 554. I’m using a Pirelly VDSL modem at home in pure routing mode (no NAT, no QoS). When starting a TCP connection to port 7070 (or 554), the Pirelli modem answers the TCP SYN with SYNACK, then it tries to connect the
Pirelli doesn’t forward port 7070 correctly Read More »
Challenge: You have a linux based firewall, which should forward all internal and external traffic of its connected clients through a VPN tunnel, and at the same time the traffic from the firewall itself should not go through the tunnel (e.g. the tunnel connection packets). Solution: There are lots of howtos for this probably. Here
Multiple Routing Tables with IPTables Read More »
If you like to search through the full Internet routing table from around the world, you can find some looking glasses at http://www.traceroute.org/ or http://www.routeviews.org/. e.g. Routeviews has telnet access to zebra servers (route-views.isc.routeviews.org,…)