Question

I got a call from a tester about a machine that was failing our software. When I examined the problem machine, I quickly realized the problem was fairly low level: Inbound network traffic works fine. Basic outbound command like ping and ssh are working fine, but anything involving the connect() call is failing with ‘No route to host’.

For example – on this particular machine this program will fail on the connect() statement for any IP address other than 127.0.0.1:

#!/usr/bin/perl -w use strict; use Socket; my ($remote,$port, $iaddr, $paddr, $proto, $line);  $remote  = shift || 'localhost'; $port    = shift || 2345;  # random port if ($port =~ /\D/) { $port = getservbyname($port, 'tcp') } die 'No port' unless $port; $iaddr   = inet_aton($remote)           || die 'no host: $remote'; $paddr   = sockaddr_in($port, $iaddr);  $proto   = getprotobyname('tcp'); socket(SOCK, PF_INET, SOCK_STREAM, $proto)      || die 'socket: $!'; connect(SOCK, $paddr)    || die 'connect: $!';  while (defined($line = <SOCK>)) {     print $line; }  close (SOCK)        || die 'close: $!'; exit; 

Any suggestions about where this machine is broken? It’s running SUSE-10.2.

Answer 1

I would check firewall configuration on that machine. It is possible for iptables (I guess your SUSE has iptables firewall) to be setup to let trough only ping ICMP packets.