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Firewalling access to 127.0.0.1 (local machine)

retep
Grafter
Posts: 182
Registered: 14-04-2007

Firewalling access to 127.0.0.1 (local machine)

I have always assumed its save to give access to 127.0.0.1 access request as its on the local machine.

http://portal.plus.net/central/forums/viewtopic.php?t=47879&postdays=0&postorder=asc&start=0

Implies its not can anyone clarify?
5 REPLIES
N/A

Firewalling access to 127.0.0.1 (local machine)

It's safe to give 127.0.0.1 access to itself, yes.

I like to vet all outgoing and incoming connections however, as lots of malware and adware likes to make outgoing connections to fetch adverts/etc, and why should I let it fetch adverts using my connection?
retep
Grafter
Posts: 182
Registered: 14-04-2007

Firewalling access to 127.0.0.1 (local machine)

Thanks I will take your word for it, its just the thread above does imply e-mails are being sent out via 127.0.0.1.

If anyone knows I am just curious how it works, are they then re-directed to the outside world and need further approval from the firewall before going out. I have seen applications first request 127.0.0.1 and then request another address which I block.
Plusnet Staff
Plusnet Staff
Posts: 12,169
Thanks: 18
Fixes: 1
Registered: 04-04-2007

Firewalling access to 127.0.0.1 (local machine)

Hi,

I can probably explain how this works. Normally the mail server (e.g. mail.plus.net for incoming or relay.plus.net for outgoing) is changed to 127.0.0.1 is changed by your anti-virus software.

The reason it does this is rather than allowing your mail client to send mail direct to the SMTP server or receive direct from the POP3 server, the AV software sets up a proxy server (on 127.0.0.1 your PC) so that it can scan all mail going in and out.

There are other ways of doing it but this usually works well because all mail has to pass through the AV software's proxy so all gets scanned.
N/A

Firewalling access to 127.0.0.1 (local machine)

Don't do this with AVG Antivirus though, that expect you to connect to the correct address, and automatically intercepts the connection to itself. This has the side effect however of any ip address at port 25 is AVG's SMTP, regardless of whether that IP actually has a mail server or not.
retep
Grafter
Posts: 182
Registered: 14-04-2007

Firewalling access to 127.0.0.1 (local machine)

Thanks for the replies.