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14

Fax delivery is NOT guaranteed - There are many ways a fax can fail. To name a few: Misdialed number Receiving fax out of paper (and not smart enough to realize) Receiving fax out of toner (and not smart enough to realize) Paper loaded upside-down in sending fax Receiving fax is a shared device and the received fax gets taken and discarded by unintended ...


13

Does it generally stand to reason that the nearer IP address A is to IP address B numerically, then the nearer IP address A is to IP address B geographically? Most definitely not. IP Netblocks are handed out by IANA to the Regional Internet Registries (RIRs), who in turn hand out netblocks to individual organizations in their region. Once ...


10

No easy way to find out or to help you without more information. Fibre connections are good for linking routers to other routers or very high end equipment to routers. If the server and the router support fibre, why not! However, as for sustained bandwidth and if 1GB/hour is possible... Follow this advice: Cheap £20 switch = bad Expensive gear = good ...


9

It depends on how well the program is written and under what credentials your server program runs as. For instance say you allocate a fixed-length buffer to read from the socket, and then you read in more than the allocated size, it might be possible to craft a server requests that overruns the buffer on the stack and overwrites the return address. At that ...


8

The switch learns the MAC-port mapping by looking at the source mac address of each incoming packet. So, the switch can build the mac table gradually. When it needs to forward a packet, it looks at the destination mac address and forwards it to the appropriate port according to the mac table. If it did not find any entry, it will sent the packet to all ...


7

By definition, if a UDP packet is dropped, the receiver cannot sent a notice back to the sender because nothing was received. You can layer your own acknowledgement system on top of UDP. Even a simple "if no data has been received in X seconds, send a packet to the sender indicating such". You can embed your own sequence numbers into the UDP packets, so that ...


7

It's often established in law that faxes are accepted documents because their delivery is 'guaranteed' Email server logs from sender and recipients are probably more reliable than fax reception confirmation. The confirmation simply implies that "a" fax answered and received the document. Server logs can confirm that "that specific" mailbox received the ...


6

ICMP is not UDP, and it's actually not even IP. It's another OSI layer 3 protocol (network layer) alongside IP. That said, it has an IP compatible header at the beginning of a packet. There is no guarantee that an ICMP packet will be delivered. It has the same delivery guarantees of any other packet on the internet: none. There are no attempts to ensure ...


6

Usually, along with UDP and ICMP which are probably the most common, but many other protocols exist and are used too. Many protocols that are considered to be legacy are still actively used today on some networks. I frequently work with legacy systems which use protocols such as LAT, DECNet, IPX. This Wiki page explains this broad topic in a fair amount of ...


6

The correct answer was staring me right in the face, though I didn't know it at the time. Apparently this little "question mark" notation on the icon is simply to alert the site admin to the fact that these bindings exist. As it turns out, you can have multiple bindings of the same protocol (say to different host aliases) and the icon will be just a globe, ...


6

When sizing a switch one thing to keep in mind as to what the "fabric" of the switch can support. Just because a 48 port switch has for example 48 Gigabit ports doesn't mean that the switch can handle all 48 ports pushing 1GB in each direction (Full Duplex) at the same time. I'm afraid however that even though some switches say they might have a 48GB fabric ...


5

A.B.C.001 and A.B.C.002 are very likely to be in close physical proximity, possibly as likely as 99% that they are on the same city block. A.B.C.001 and A.B.C.254 are only slightly less likely to be so. A.B.001.D and A.B.002.D are less likely still, perhaps 90%, for a 256x as large definition of "close". A.B.001.D and A.B.254.D slightly less likey again. ...


5

The problem is probably that ping doesn't handle IPv6, it's a tool from the good old IPv4 days. Since it doesn't recognize ::1 as a valid IPv4 address, it'll try to resolve it like a domain. For some reason, the DNS server you're using responds with a valid IPv4 address for this "domain". To ping the IPv6 address, use ping6 ::1, which should yield answers ...


5

You could probably use tcptraceroute to see where it gets blocked: $ sudo tcptraceroute ruminant.bitfolk.com 22 Selected device eth0, address 192.168.0.8, port 49071 for outgoing packets Tracing the path to ruminant.bitfolk.com (85.119.82.121) on TCP port 22 (ssh), 30 hops max 1 192.168.0.7 0.978 ms 0.556 ms 0.697 ms 2 192.168.1.1 1.587 ms 1.667 ms ...


5

From my understanding, "Cisco IPSec" is just marketing speak for IPSec with some pre-defined settings for AH/ESP, tunnel/transport mode, etc. pp. When you read the RFCs, you see that they deliberately leave room for implementations...you, as the network admin setting up the IPSec connection have quite a lot of options to choose from for the protocol (and ...


5

CIFS is an implementation of SMB. For all intents and purposes they are the same thing.


5

In general, yes, it is TCP/IP. Even if there is no connection to the internet, TCP/IP is still in use for the internal network.


4

ZeroMQ has been designed as an asynchronous transport/message protocol. If one of your nodes goes down, it will re-stablish the ZMQ-Socket and continue sending its messages when the route to the target endpoint comes back up. Performance is good and according to its IRC channel it's well tested enough nowadays to use over WAN.


4

But which application-layer protocol do the clients use in the LAN to communicate with the servers? Is the data simply transferred via ethernet as well? Clients don't care how the storage is presented to the servers. If it's FCP, iSCSI, or whatever on the server, it's just a block device to the server and can be presented to the clients however you ...


4

To block certain IP addresses (or hostnames) from accessing your website, you could use Apache's Allow and Deny directives, something like what sukru said. But it's often considered more secure to completely block any communication (not just website access) between the selected IPs and your server - after all, if you have reason enough to keep them from ...


4

You can use Nmap's snmp-brute something like nmap -sU -p161 --script snmp-brute --script-args snmplist=community.lst 192.168.1.0/24


4

I would advice against doing this using an iptables redirect. The reason is that when someone browses your site using HTTP, their browser is not expecting an SSL session handshake. It may work, but it's definitely not guaranteed to. Instead, I'd have a separate Apache instance (or a VirtualHost) that listens on port 80. That apache instance/VH should be ...


4

The Glasnost tool will do some of what you're looking for, and the tool is BSD licensed. This is a client/server tool. I think you could build some useful scripts using nmap and its built-in scripting functionality fairly easily, as well. Having "known good" servers on the Internet that you can make connection attempts to would certainly be a requirement ...


4

I think it's actually more debated than you make it appear. There is an admittedly old, related Linux FAQ: http://www.tldp.org/HOWTO/VPN-HOWTO/ I've used a PPP-over-ssh-over-ADSL for more than 12 years, and it never failed me, so from my experience I'd dare to say that the doomsayers probably largely exaggerate. TCP over TCP is probably a bad idea with RTC ...


3

The Google term you're looking for is "Looking Glass". Try Hurricane Electric's, at http://lg.he.net/, to get an idea.


3

You need to update httpd.conf (or .htaccess if sufficient options are enabled) <Location /url> Order allow,deny Allow from all Deny from host1 Deny from host2 Deny from *.domain ...etc </Location> From documentation: link Allow,Deny First, all Allow directives are evaluated; at least one must match, or the request is ...


3

You'll have to read more about Geolocation Software and their different types of data gathering techniques. Most online services aimed at geolocation do a regional internet registry lookup, in the U.S. it would be ARIN. There are various types of techniques and accuracy in finding out an actual location, some even combine methods in order to give you their ...


3

You know, not only does numeric "closeness" not have any direct relation on geographical closeness, with the widespread use of NAT there's not even any guarantee that requests from the SAME IP have any geographic relation to each other, in terms of the geographic location of the end user or machine making the request. There are plenty of corporate networks ...



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