Hi Alex Not sure if you saw my post, but I mentioned that I've managed to send emails out while on the Telstra network via my iPad and the only outgoing server I use with it is iinet with Authentication. (which is my home ISP) I also mentioned I use my iPhone with 4 different outgoing SMTP servers and they all work and I never have email held or stuck.
Kind Regards Daniel On 26/6/10 8:18 PM, "Alexander Hartner" <a...@j2anywhere.com> wrote: > Hi Ronni, > > If this measure is to prevent infected PC from pretending they are mail > servers it will definitely not work. Why would a spammer route their traffic > through the invested user's ISP default mail gateway. They would simply > delivery it directly to the intended final destination. The same goes for > spammers. They would simply setup their own mail server. What they would not > do, is use a 3G service provider for this as wireless data is simply too > expensive. So as far this measure only prevents me from send email via my own > mail server while connected to my ISP's network. Also in some cases upgrading > to what they call business packages does not offer this "feature" > > http://forums.whirlpool.net.au/forum-replies-archive.cfm/205551.html > "BigPond Dialup Business have plans that allow mail servers to be setup > (particular for those that have static IPs associated with them. > The BP Business MegaPOP numbers do not block port 25 to allow customers to > continue hosting their own mail servers. > ... > Telstra has only blocked port 25 for DHCP allocated IP's. If you use a static > IP, port 25 is available." > > As seems to be the case it doesn't even require any form of authentication nor > do they verify that the purported sender is in fact valid. This in itself if > far worth in my opinion as the alternative currently implemented. For example > this lets just about anyone pretend they are anyone else. Try it for yourself > : http://www.yuki-onna.co.uk/email/smtp.html You can have a lot of fun sending > yourself an email from your Boss giving you the day off. > > In my experience most ISPs do allow access to other mail servers. Otherwise > every small company hosting it's own mail server would only be able to send > email from inside its own network. > > There are also other implications of sending your email via a third party mail > server like bigpond. As Ronnie already mentioned the ISP can and most likely > is monitoring your email. For most of us this is not really an issue, but on > the other hand how would you feel if somebody kept tabs on who you send when > and maybe even what. > > Ronnie, how did you configure you mobile to send via Mobile Me. Via the > alternate port ? I completely agree with you that iPhone OS 4.0 had nothing to > do with this. > > What would help me a lot is to find out with wireless 3g service providers > block port 25 and which ones don't. In the UK for example, neither T-Mobile, > O2 nor Orange do this. I hope you forgive me. I do understand that when in > Rome.... > > Thanks for all your help and feedback > Alex > > > > On 26 Jun 2010, at 16:09, Ronda Brown wrote: > >> Hi Alex, >> >> On 26/06/2010, at 2:12 PM, Alexander Hartner wrote: >> >>> The problem is that blocking port 25 does nothing to reduce spam, >> >> I don't agree with your comment that blocking port 25 does nothing to reduce >> spam. >> >> Mail servers communicate with other mail servers using port 25. Allowing >> unrestricted access to external servers through port 25 just permits infected >> PC¹s to pretend they are mail servers, sending mail directly to any other >> mail server on the Internet without having to have email access, >> authentication or privileges on any legitimate system. >> >> ISP blocking of port 25/465 cripples the existing zombie botnets, leaving >> them unable to spam, but has no effect whatsoever on mail server to mail >> server traffic. >> >> Port 25 Blocking disrupts viruses and malware programs that get on ISP >> customer machines and send out spam emails. >> The emails must now be sent through the ISP's mail server so they can monitor >> the volume of email and control spam sent through their systems. >> >> While blocking Port 25/465 won¹t end spam, it does make it much more >> difficult for spammers to send the volume of email they do using infected >> PCs. >> >> It will also have the effect of sparing a lot of small business from having >> their mail servers relentlessly pounded to the point of crawling or crashing >> altogether. >> >> Almost any current email client can send outbound mail through the mail >> server of your choice using port 587. >> This being the actual port, as specified by RFC 4409 for such client >> submission. >> >> >>> and realistically what spammer uses their mobile? >>> >>> The problem with forcing users to set an alternate SMTP server is that it >>> break SPF (http://en.wikipedia.org/wiki/Sender_Policy_Framework) which does >>> a much better job at reducing spam. With SPF each domain specified a server >>> which is the designated mail server for that domain. On the receiving end >>> when a message is received, the receiving server can then check via the >>> public DNS record whether the message originated from the authorised server. >>> This ensures that the email came from it's proper origin. Most domain owners >>> would take their own precaution to prevent anyone form using their mail >>> server to distribute spam, or they will find themselves being blacklisted >>> very quickly. >>> >>> What telstra and bigpond allow all their clients to send emails with the >>> sender having the option to choose just about any sender address. This is >>> typically considered very poor form, as it would allow me for example to >>> send a message which to most users would look like it came from somebody >>> else. The technical term for this is an "open relay" and is a real problem. >>> >>> I guess this has been a problem for some time and will be not addressed any >>> time soon. >> >> Again I mention: Most, if not all internet service providers block the use of >> SMTP servers that are outside of their network or not provided by the ISP >> being used for your internet connection at the time unless the SMTP server is >> authenticated. This restriction is part of an overall effort to prevent spam >> emanating from the ISP's domain and when connected to a cellular internet >> network for internet access is no exception. >> >> This has been in place and an issue for a long time - well before the iPhone, >> iPod Touch, and iPad were introduced that firmware update 4.0 can't do >> anything about. >> >>> >>> Are there any 3G service providers which do not do this ? >> >> Most ISPs don't provide an authenticated SMTP server, but a number of other >> email account providers do. >> Apple does with a MobileMe account, and so does Google with a Gmail account >> to name only two. >> >> I use my MobileMe Account to send from when on Telstra's 3G Network. >> >> Cheers, >> Ronni >> >> 17" MacBook Pro Intel Core i7 >> 2.66GHz / 4GB / 1067 MHz DDR3 / 500GB Serial ATA Drive @ 7200rpm >> >> OS X 10.6.3 Snow Leopard >> Windows 7 Ultimate (under sufferance) >> >> >> >> >> >> >> >> -- The WA Macintosh User Group Mailing List -- >> Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> >> Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> >> Unsubscribe - <mailto:wamug-unsubscr...@wamug.org.au> > > > > -- The WA Macintosh User Group Mailing List -- > Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> > Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> > Unsubscribe - <mailto:wamug-unsubscr...@wamug.org.au> > --- Daniel Kerr MacWizardry Phone: 0414 795 960 Email: <daniel @ macwizardry . com . au> Web: <http://www.macwizardry.com.au> **For everything Macintosh** -- The WA Macintosh User Group Mailing List -- Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> Unsubscribe - <mailto:wamug-unsubscr...@wamug.org.au>
