Comment 5 for bug 306007

AlainKnaff's comment #3 is entirely correct. This bug is also easy to reproduce, as described in the initial comment, although as noted in comment #3, it is not tabs per se that are the problem: anything other than '#' or end-of-line is a problem.

I encountered this with ypbind taking the port 631 of cups, causing printing in GNOME to be disabled.

Most casual users will not report this bug because it will "go away on its own" if they reboot or something--but that is not the attitude to encourage.

Just to be completely specific about how to reproduce this (this was with 8.04, but I don't have any reason to believe it's been fixed):

0. Backup the file:
$ sudo mv /etc/bindresvport.blacklist /etc/bindresvport.blacklist.bak

1. Reserve all ports 600-999, with the format used for shipped bindresvport.blacklist (e.g., "631\t# cups")
$ perl -e 'for ($i=600; $i<1000; $i++) {print "$i\t# foo\n";}' | sudo dd of=/etc/bindresvport.blacklist
7+1 records in
7+1 records out
4011 bytes (4.0 kB) copied, 6.5962e-05 s, 60.8 MB/s

2. Restart nis (or a different service as available).
$ sudo /etc/init.d/nis restart
 * Starting NIS service

3. Check what port it got:
$ sudo netstat --inet -nap | grep ypbind
tcp 0 0 0.0.0.0:724 0.0.0.0:* LISTEN 29803/ypbind
udp 0 0 0.0.0.0:723 0.0.0.0:* 29803/ypbind
udp 0 0 0.0.0.0:724 0.0.0.0:* 29803/ypbind

4. Note that it falls in the range 600-999 (there is a small 24 out of 424 chance it will not -- try again).

This also fails with spaces, substituting the perl command in step 1:
$ perl -e 'for ($i=600; $i<1000; $i++) {print "$i # foo\n";}' | sudo dd of=/etc/bindresvport.blacklist

It works with the '#' character directly following the port number:
$ perl -e 'for ($i=600; $i<1000; $i++) {print "$i# foo\n";}' | sudo dd of=/etc/bindresvport.blacklist
or with the port number on the line by itself:
$ perl -e 'for ($i=600; $i<1000; $i++) {print "$i\n";}' | sudo dd of=/etc/bindresvport.blacklist

In the last two cases I get:
tcp 0 0 0.0.0.0:1001 0.0.0.0:* LISTEN 29923/ypbind
udp 0 0 0.0.0.0:1000 0.0.0.0:* 29923/ypbind
udp 0 0 0.0.0.0:1001 0.0.0.0:* 29923/ypbind

The comment #3 also describes the fix.