Continued concerns about the use of anonymizing proxy IP addresses prompted an effort last week to implement widespread blocks of such IPs, but technical problems forced the project to be put on hold.

These IPs, known as open proxies, have a reputation for being primarily a source of vandalism, as well as being used by blocked users to circumvent their editing restrictions. To deal with the problem, Fvw made a proposal to use a bot that would identify and block such proxies.

Routine blocking of open proxies originally began in February 2004 after discussion on the English Wikipedia mailing list. It was initially done by having the servers scan IP addresses when they attempted to edit, and blocking those that were identified as proxies. However, the regular scanning was disabled after a while. Since then, administrators have blocked open proxies when they are discovered editing Wikipedia, rather than trying to identify them systematically.

Fvw initially proposed running a bot to block proxies on 23 January. He offered to collect lists from websites that publish the IPs of anonymizing proxies, verify them and then block the IP.

Korath raised some concerns, first of all with having a bot use admin privileges, and the possibility that innocent victims of a trojan horse might get blocked. In response, Fvw pointed out that proxies would not be blocked based on scans, which would create fewer such problems, and that a real administrator would be likely to block the proxy if discovered just as the bot would. Nearly all of the other comments on Wikipedia talk:Bots were supportive of Fvw's idea.

When Fvw actually began running the bot last Thursday, however, new problems came up and forced him to shut down the bot. According to Jamesday, the current block-checking code is executed every time someone tries to edit a page, and the work involved is dependent on the cumulative total of blocks in place, with the potential to slow the technical side of the editing process considerably. Accordingly, he asked, "If you're aware of any blocks not in place to deal with actual vandalism, please remove them until the programming changes are known to be in place on the live site."

Improved code to deal with these issues may be in place in a few months. In the meantime, Fvw undid the bot-created blocks pending the application of a fix for the problem.