How do I send a L2TP packet in scapy?

0
votes

I am actually new to scapy/networking

Like for ICMP I can send a ICMP packet/request like 

srp(Ether(src=u'd2:ff:90:c5:1f:21', dst=u'9c:22:14:4f:6c:ac', type=2048)/IP(src=u'238.166.15.14', dst=u'70.74.2.83')/ICMP(type=8)/Raw(load='UZe5ICdH'),timeout=10,iface="ens192.50")

on the other side I can send a packet/reply like

srp(Ether(dst=u'd2:ff:90:c5:1f:21', src=u'9c:22:14:4f:6c:ac', type=2048)/IP(dst=u'238.166.15.14', src=u'70.74.2.83')/ICMP(type=0)/Raw(load='UZe5ICdH'),timeout=10,iface="ens192.50")

Can some one help me with L2TP ?

1
pythonwiresharkscapytcpdump

1 Answers

0
votes

LT2P uses UDP packets underlying over 1701 port to communicate.

Packet structure for L2TP is as below:

Ether / IP / UDP/ L2TP / PADDING

So we will be sending a packet like 

srp(Ether(src=u'12:24:52:93:c6:54', dst=u'ea:26:7c:6b:02:dc', type=2048)/IP(src=u'22.159.236.164', dst=u'182.187.41.246')/UDP(dport=1701, sport=1701)/L2TP(pkt_type=2)/Padding(load='5Z0WZ'), iface='ens192.50', timeout=5)

Here am sending a message packet over l2tp (i.e pkt_type=2). We can also send control messages too, like Start-Control-Connection-Request, Hello etc.

Reference sites: