Whenever I open some help within eclipse I get a page saying:
Server Error. The following error occurred: [code=CANT_CONNECT_LOOPBACK] Cannot connect due to potential loopback problems
I’m running Ubuntu 10.04.
Any ideas what this can be?
UPDATE
Some commands outputs (some private info replaced):
$ ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:xx:xx:xx:xx:xx
inet addr:123.12.123.235 Bcast:123.12.456.255 Mask:255.255.254.0
inet6 addr: fe80::xxx:eff:xxxx:xxxx/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1343040 errors:0 dropped:0 overruns:0 frame:0
TX packets:1133672 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:829265876 (829.2 MB) TX bytes:242912202 (242.9 MB)
Memory:f3200000-f3220000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:125 errors:0 dropped:0 overruns:0 frame:0
TX packets:125 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:15910 (15.9 KB) TX bytes:15910 (15.9 KB)
$ route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
123.12.123.0 0.0.0.0 255.255.254.0 U 1 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0
0.0.0.0 123.12.456.254 0.0.0.0 UG 0 0 0 eth0
$ sudo netstat -anp
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 765/portmap
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 871/sshd
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 1181/cupsd
tcp 0 0 0.0.0.0:52068 0.0.0.0:* LISTEN 786/rpc.statd
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 1186/mysqld
tcp 0 0 0.0.0.0:53709 0.0.0.0:* LISTEN -
tcp 0 0 123.12.123.235:755 123.12.5.48:2049 ESTABLISHED -
tcp 0 0 123.12.123.235:60793 123.12.5.129:8080 ESTABLISHED 2264/firefox-bin
tcp 0 0 123.12.123.235:57940 123.12.5.43:8080 ESTABLISHED 2264/firefox-bin
tcp 0 0 123.12.123.235:57928 123.12.5.43:8080 CLOSE_WAIT 2247/google-chrome
tcp 0 0 123.12.123.235:35767 123.12.5.129:8080 ESTABLISHED 2247/google-chrome
tcp 0 0 123.12.123.235:57930 123.12.5.43:8080 ESTABLISHED 2247/google-chrome
tcp 0 0 123.12.123.235:57931 123.12.5.43:8080 CLOSE_WAIT 2247/google-chrome
tcp6 0 0 :::80 :::* LISTEN 1278/apache2
tcp6 0 0 :::22 :::* LISTEN 871/sshd
tcp6 0 0 ::1:631 :::* LISTEN 1181/cupsd
tcp6 0 0 :::55934 :::* LISTEN 1956/eclipse
tcp6 0 0 :::5900 :::* LISTEN 1792/vino-server
udp 0 0 0.0.0.0:35631 0.0.0.0:* 912/avahi-daemon: r
udp 0 0 0.0.0.0:962 0.0.0.0:* 786/rpc.statd
udp 0 0 0.0.0.0:68 0.0.0.0:* 1575/dhclient
udp 0 0 0.0.0.0:46149 0.0.0.0:* -
udp 0 0 0.0.0.0:5353 0.0.0.0:* 912/avahi-daemon: r
udp 0 0 0.0.0.0:111 0.0.0.0:* 765/portmap
udp 0 0 0.0.0.0:36211 0.0.0.0:* 786/rpc.statd
udp 0 0 123.12.123.235:123 0.0.0.0:* 1689/ntpd
udp 0 0 127.0.0.1:123 0.0.0.0:* 1689/ntpd
udp 0 0 0.0.0.0:123 0.0.0.0:* 1689/ntpd
udp6 0 0 fe80::227:eff:fe07::123 :::* 1689/ntpd
udp6 0 0 ::1:123 :::* 1689/ntpd
udp6 0 0 :::123 :::* 1689/ntpd
Active UNIX domain sockets (servers and established) due to post size limit.
UPDATE 2
My proxy bypass settings:
I know this is a late answer, but I had the same problem and resolved it, so to tie up this one…
This is a combination of two bugs:
(i) Eclipse’s internal help browser doesn’t use the Eclipse proxy settings! See:
https://bugs.eclipse.org/bugs/show_bug.cgi?id=318969
(and the bugs referenced in comment #7 therein)
(ii) Ubuntu’s proxy support is horribly broken in certain subtle ways. See:
https://bugs.launchpad.net/ubuntu/+bug/300271
The fix/workaround is to manually set the no_proxy environment variable before running eclipse (as reported in the Eclipse #308035 bug referenced from the 318969 one) e.g.
Help then launches correctly within Eclipse. Of course, once Eclipse is launched (thus running its own internal HTTP server), you can also access the local help manually from another browser (or, if within the ‘can’t access 127.0.0.1’ screen, there’s an icon at the top to launch in an external window –> default system browser).
This may well apply on other Linux distros using Gnome.
[Couldn’t post the 308035 bug link because my low reputation means I can only post 2 hyperlinks 🙁 Getting excited at this privilege come 10 reputation points :-)]