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- To: tlug@example.com
- Subject: Re: tlug: Netmask question
- From: Julien Beasley <jbb@example.com>
- Date: Mon, 21 Feb 2000 16:51:41 +0900 (JST)
- Content-Type: TEXT/PLAIN; charset=US-ASCII
- In-Reply-To: <Pine.LNX.3.95.1000221125809.8052E-100000@example.com>
- Reply-To: tlug@example.com
- Sender: owner-tlug@example.com
On Mon, 21 Feb 2000, Selva Nair wrote: > > > On Mon, 21 Feb 2000, Julien Beasley wrote: > > > Hello everyone, > > > > I have a problem that I'm sure is simple to solve, but I've been stumped > > on this. > > > > When I connect via ppp to my ISP via gol, I am assigned an ip that is one > > of the following forms: > > > > xxx.yyy.8.zzz > > xxx.yyy.9.zzz > > xxx.yyy.10.zzz > > Guess you dont mean three identical digits by xxx, yyy etc. It may be > useful to know the last byte to see (from the subnet mask) which subnet > you belong to in each case. No, they are not the same three digits =). I just didn't remember off the top of my head what they were. > > When I connect, I can always ping outside computers and do nslookup > > regardless of which kind of ip I am assigned. However, I can only telnet, > > irc, and www if I am assiged an ip of the form: > > > > xxx.yyy.8.zzz > > > > > > So I can ping regardless of which ip I was assigned, but I can only use > > other protocols if I have an ip that ends in xxx.yyy.8.zzz > > > > I happen to be using IP masquerading on this computer but I don't _think_ > > that has anything to do with it. The other computers behind the masq > > behave the same way as the gateway computer. If the linux box has an 8.zzz > > ip, the computer behind the masq can www and telnet. If not, it can only > > ping. > > > > If I do an /sbin/ifconfig, it tells me that the netmask on my ppp > > connection is 225.225.225.225. Is that wrong? > > If that is really the (sub)-netmask it is wrong. But do you mean > 255.255.255.225? Even that is unusual as 225 will be a non-contigous bit > mask, something not very common (though the standard (RFC 950) does > permit it). I suppose that you are using dhcp, so that the netmask and > gateway addresses are obtained from the ISP's server. Do you have the > same subnet mask for the all three IP addresses you mentioned? Also can > we see the output of ipconfig ? Sorry, typ. it's 255.255.255.255. Yes, the subnet mask is always the same. Tomorrow I'll bring my laptop to work and cat ifconfig and netstat > > How can it be that I can ping in any case but I can only telnet and www if > > I have an 8.zzz ip? > > > > I have no clear idea, but a possible guess is that you have some ppp > option (say header compression) which your server doesn't support. > ICMP packets of ping may get thru but not TCP packets of telnet. > But first let us get the netmask right. Ok, thank you. I'll have more detail tomorrow Julien -------------------------------------------------------------------- Next Technical Meeting: March 11 (Sat) 13:00 Temple University Japan * Topic: "What's new in Perl 5.6" Guest speaker: Simon Cozens (TLUG Perl guru) Next Nomikai Meeting: April 21 (Fri) 19:00 Tengu TokyoEkiMae -------------------------------------------------------------------- more info: http://www.tlug.gr.jp Sponsor: Global Online Japan
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- Re: tlug: Netmask question
- From: Selva Nair <selva@example.com>
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