Networks
SMTP
MAIL FROM:<a@example.com>
RCPT TO:<b@example.com>
RCPT TO:<c@example.com>
DATA
Subject: Test 01
FROM: a@example.com
To: b@example.com, c@example.com
Good morning
.
(it has to end with a line with a single dot in it)
POP3
pass userpass
list
retr nr
dele nr
quit
IMAP
S: a0001 OK LOGIN Ok.
C: a0002 LIST "" ""
S: * LIST (Noselect) "." ""
S: a0002 OK LIST completed
C: a0003 LSUB "" "*"
S: * LSUB (Marked HasChildren) "." "INBOX"
S: * LSUB (Unmarked HasNoChildren) "." "INBOX.Drafts"
S: * LSUB ...
C: a0004 SELECT "INBOX.test"
S: * FLAGS (Draft Answered Flagged Deleted Seen Recent)
S: * OK [PERMANENTFLAGS (* Draft Answered Flagged Deleted Seen)] Limited
S: * 1 EXISTS
S: * 0 RECENT
S: * OK [UIDVALIDITY 1129647005] Ok
S: * OK [MYRIGHTS "acdilrsw"] ACL
S: a0004 OK [READ-WRITE] Ok
C: a0005 FETCH 1:4 (UID FLAGS)
S: * 1 FETCH (UID 1049 FLAGS (Seen))
S: * 2 FETCH (UID 1113 FLAGS (Seen))
S: * 3 FETCH (UID 1114 FLAGS (Seen))
C: a0006 SEARCH UNSEEN
S: * SEARCH 9
C: a0007 UID FETCH 9 BODY.PEEK[]
S: * 1 FETCH (UID 9 BODY[] {14111}
C: A008 LOGOUT
S: * BYE ...
HTTP
Host: www.example.com
User-Agent: telnet
Accept: text/xml,application/xml,application/xhtml+xml,text/html,text/plain
Accept-Language: de,en
Referer: http://foo.examle.com
httpie is a nicer curl
Testing local web servers with their official hostnames
Webservers are usually configured to only respond to their official domain names. This becomes a problem when you want to test them locally before they go live. This is how you can test a local webserver with the IP 192.168.0.1 that has been configured to listen to www.example.com:
If you use https you need to do this
CORS Cross-Origin Resource Sharing
- You are using in your browser a website A. You have there some privileges, maybe because you authenticated, or your IP, ...
- You also have in your browser another website B opened
- Now B can send via JavaScript a request to website A and A will think it actually comes from you and not from some other website because it runs in your browser.
As this is dangerous such requests will be blocked in your browser. In order to make it work
- the request from B needs to have an Origin header that explains that it comes from B
- the response from A needs to have an Access-Control-Allow-Origin that matches the Origin header.
Example
< HTTP/1.1 200 OK
< Access-Control-Allow-Credentials: true
< Access-Control-Allow-Origin: http://example.com
IP
IPV4
| ipv4 Mask | Constant Parts | |
|---|---|---|
| /32 | Everything, only one machine (255.255.255.255) | |
| /24 | Everything but the last block (255.255.255.0) | |
| /8 | Only the first block (255.0.0.0) | |
| /0 | Nothing, all machines (0.0.0.0) | |
IPV6
IPV6 An IPV6 address consists of 8 blocks with 4 Hex numbers (which are 16 bits). The whole address has 128 bits. In each Block you can skip the leading 0 and one complete 0 area can be written as ::.
A single IPV6 address:
A network where all addresses in the same network only differ in the last Hex number
A smaller number behind the / is a larger network
2001:1db8:85a3:28d3:1319:8a2e:3374:0/112
2001:1db8:85a3:28d3:1319:8a2e:3374::/112
2001:1db8:85a3:28d3:1319:8a2e::/96
2001:1db8:85a3:28d3:1319::/80
2001:1db8:85a3:28d3::/64
2001:1db8:85a3::/48
2001:1db8::/32
2001::/16
fd00::/8
A normal uplink provider gets a /32, normal people get a /64 network.
Special addresses No address:
Localhost
Link local, each interfaces generates this automatically.
Successor for the private IPV4 addresses, deprecated
Successor of the successor of the private IPV4 addresses. Formed like this
Here is fd the prefix for local generated ULAs, 9e:21a7:a92c a random value for your network and is a Subnet for you.
Similar, but assigned globally.
Multicast
Examples:
www.google.com has IPv6 address 2a00:1450:4005:808::1012
eth0 Link encap:Ethernet Hardware Adresse 00:1e:8c:ab:cd:12
inet Adresse:10.0.0.4 Bcast:10.0.0.255 Maske:255.255.255.0
inet6-Adresse: fe80::21e:8cff:feab:cd12/64
# ping6 -I eth0 fe80::21e:8cff:feab:cd12
Ping one ipv6 IP in the local network
DNS
How do DNS request work There are 13 DNS root servers. You first ask one of them who is responsible for the section
;; QUESTION SECTION:
;www.tgunkel.de. IN A
;; AUTHORITY SECTION:
de. 172800 IN NS s.de.net.
de. 172800 IN NS n.de.net.
de. 172800 IN NS a.nic.de.
de. 172800 IN NS f.nic.de.
de. 172800 IN NS l.de.net.
de. 172800 IN NS z.nic.de.
You can now cache the result so you do not need to ask again for the next .de domain. It is supposed to be valid for 172800/(60*60)=48 hours.
Pick any of the nameservers for that section and ask again
;; QUESTION SECTION:
;www.tgunkel.de. IN A
;; AUTHORITY SECTION:
tgunkel.de. 86400 IN NS ns2.hans.hosteurope.de.
Now you know which server is responsible for that domain. That can again be cached. 86400/(60*60)=24 hours
;; QUESTION SECTION:
;www.tgunkel.de. IN A
;; ANSWER SECTION:
www.tgunkel.de. 3600 IN CNAME tgunkel.de.
This is the final answer. This one is valid for 3600/(60*60)=1 hour.
Get current dns settings
nmap
Find all ssh servers
nmap -p 22 --open -sV 192.168.178.0-255
Linux Bonding
One Linux computer with at least 2 network cards. Connect your network cards with one or more normal switches.
Advantage: Higher network performance and if one of the network cables fails the connection is not interrupted.
allow eth0
iface eth0 inet dhcp
allow eth1
iface eth1 inet dhcp
auto bond0
iface bond0 inet dhcp
bond-mode 6
bond-miimon 1000
bond-slaves eth0 eth1
Now you have one virtual network device called bond0 which distributes the data on both real cards eth0 and eth1. If one looses connection this will be detected and the data will be transferred by the remaining cards
bonding: bond0: making interface eth1 the new active one.
Look into packages
tcpdump -A -s 10240 '(((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | egrep --line-buffered "^........(GET |HTTP\/|POST |HEAD )|^[A-Za-z0-9-]+: " | sed -r 's/^........(GET |HTTP\/|POST |HEAD )/\n\1/g' | grep \ HTTP
ngrep is a nicer tcpdump
Configurate Modem
e.g. with minicom
| Dial Nr |
ATL[''1'']
ATL[''2'']
ATL[''3'']
| Speaker Volume Level [x] |
ATX[''4'']
| [3]=Ignores busy and honours dial-tone, [4]=Honours busy and dial-tone |
ATM[''1'']
ATM[''2'']
| [0]=Speaker off, [1]=Speaker on while dialling, [2]=Speaker on |
| Save |