How to allow SSH over PPP?

I have these two computers connected through ppp. One has ip 10.10.0.1 and the other has ip 10.10.0.2. Both also have the interface ppp0 with netmask 255.255.255.255:

# ifconfig
ppp0: flags=4305  mtu 1500
        inet 10.10.0.2  netmask 255.255.255.255  destination 10.10.0.1
        ppp  txqueuelen 3  (Point-to-Point Protocol)
        RX packets 7  bytes 105 (105.0 B)
        RX errors 3  dropped 0  overruns 0  frame 0
        TX packets 20  bytes 1522 (1.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

How can I make it possible to connect from 10.10.0.2 into 10.10.0.1 using SSH? If I make:

# ssh -vv root@10.10.0.1

I can see that it gets frozen at:

.
.
.
password: 
debug2: input_userauth_info_req
debug2: input_userauth_info_req: num_prompts 0
debug1: Authentication succeeded (keyboard-interactive).
Authenticated to 10.10.0.1 ([10.10.0.1]:22).
debug1: channel 0: new [client-session]
debug2: channel 0: send open
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug1: pledge: network

Watching everything from tcpdump I see this:

# tcpdump -i ppp0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on ppp0, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes
22:15:48.592651 IP tlcmelo > 10.100.0.1: ICMP echo request, id 17288, seq 1, length 64
22:15:48.942907 IP 10.100.0.1 > tlcmelo: ICMP echo reply, id 17288, seq 1, length 64
22:15:49.593728 IP tlcmelo > 10.100.0.1: ICMP echo request, id 17288, seq 2, length 64
22:15:49.821594 IP 10.100.0.1 > tlcmelo: ICMP echo reply, id 17288, seq 2, length 64
22:15:50.595483 IP tlcmelo > 10.100.0.1: ICMP echo request, id 17288, seq 3, length 64
22:15:50.840112 IP 10.100.0.1 > tlcmelo: ICMP echo reply, id 17288, seq 3, length 64
22:15:51.597014 IP tlcmelo > 10.100.0.1: ICMP echo request, id 17288, seq 4, length 64
22:16:00.105020 IP tlcmelo.57621 > 10.100.0.1.57621: UDP, length 44
22:16:38.104153 IP tlcmelo.57621 > 10.100.0.1.57621: UDP, length 44
22:17:04.490191 IP tlcmelo.37489 > 239.255.255.250.1900: UDP, length 171
22:17:05.490773 IP tlcmelo.37489 > 239.255.255.250.1900: UDP, length 171
22:17:06.491775 IP tlcmelo.37489 > 239.255.255.250.1900: UDP, length 171
22:17:07.492280 IP tlcmelo.37489 > 239.255.255.250.1900: UDP, length 171
22:17:16.104112 IP tlcmelo.57621 > 10.100.0.1.57621: UDP, length 44
22:17:54.103994 IP tlcmelo.57621 > 10.100.0.1.57621: UDP, length 44
22:18:32.105034 IP tlcmelo.57621 > 10.100.0.1.57621: UDP, length 44

-------- Edit 1: @derobert, thanks for your message: It is not possible also to ssh from 10.10.0.1 back to 10.10.0.2, same issue actually. I tried a smaller MTU, no success unfortunately. @pizdelect, thanks for your message: I am running debian in both computers. I tried setting MTU to 1000 and 500, no success yet. Edit 2: In the 10.10.0.1, doing iptables -vL I see these: Chain Block (2 references) pkts bytes target prot opt in out source destination 75 3210 LOG all -- any any anywhere !0.0.0.255/-1 limit: avg 3/hour burst 5 LOG level warning prefix "Iptables: Block: " 6 360 REJECT tcp -- any any anywhere anywhere reject-with tcp-reset 2433 143K REJECT udp -- any any anywhere anywhere reject-with icmp-port-unreachable 0 0 DROP all -- any any anywhere anywhere Is that possible that it is blocking the connection?