clyde@cs.utexas.edu (Head UNIX Hacquer) (05/12/89)
Problem: The time-to-live value for TCP/IP packets is too small to reach some hosts. Index: /sys/netinet/tcp_timer.h 4.2 BSD, UMAX 3.X, SunOS 3.X Description: Some hosts are reachable with ping(8) but cannot sustain TCP connections. Repeat-By: FTP to 'reagan.ai.mit.edu' from 'emx.utexas.edu'. Fix: Increase TCP_TTL in /sys/netinet/tcp_timer.h to a MUCH larger value. The 4.2BSD ttl of 15 is not sufficent. Many other systems with 4.2BSD derived TCP/IP implimentations (SunOS 3.X, Encore UMAX 3.X, DYNIX 3.0.4 and Wollongong VMS TCP/IP at least) suffer from this. It is not clear that the 4.3BSD value of 30 will be sufficent in the future. With the demise of ARPANET, sites that were only 2 or 3 hops away are now 6 or 10 hops away (such as the U of Texas). Local routers (gateways) cause even more hops to be taken, requiring a longer TTL for a TCP packet to survive to where it needs to go. Shouter-To-Dead-Parrots @ Univ. of Texas Computation Center; Austin, Texas clyde@emx.utexas.edu; ...!cs.utexas.edu!ut-emx!clyde Tip #268: Don't feel insecure or inferior! Remember, you're ORGANIC!! You could win an argument with almost any rock!