My TTL changing over every packetand I don't know why
Recently I discovered that some pings sent to me were giving a TTL
error. When someone pings my computer, it shows a different TTL
value for every packet.
For example, ping.eu shows that:
--- PING 78.188.216.242 (78.188.216.242) 56(84) bytes of data. ---
64 bytes from 78.188.216.242: icmp_req=1 ttl=112 time=78.7 ms
64 bytes from 78.188.216.242: icmp_req=2 ttl=17 time=78.8 ms
64 bytes from 78.188.216.242: icmp_req=3 ttl=206 time=78.7 ms
64 bytes from 78.188.216.242: icmp_req=4 ttl=212 time=78.7 ms
--- 78.188.216.242 ping statistics ---
packets transmitted 4
received 4
packet loss 0 %
time 3002 ms
--- Round Trip Time (rtt) ---
min 78.734 ms
avg 78.782 ms
max 78.861 ms
mdev 0.050 ms
(And sometimes I see request timed out
and TTL expired
errors as well.)
As you can see, every packet has a different TTL
value. Is that a problem? If it is, is it caused by my network configuration, or is it caused by my ISP? And what can I do in this situation?
If it matters, I use a WRT54GH
home router with ZyXEL ADLS
bridge modem, connecting three Windows computers. You can try to ping me at my IP address, 78.188.216.242
.
Solution 1:
I got similar results pinging your IP address from the US.
When I pinged 81.212.77.58, the next hop upstream from you, which I presume is your ISP's equipment, I got back a TTL of 243 every time. This is obviously wrong.
The next hop upstream from that acted reasonably, with a TTL of 54 every time.
My strong suspicion based on these results is that your ISP is mangling the packets.
Solution 2:
Providing your not pinging yourself the TTLs that come back are the TTL values of the received ping packet. There is little you can do to manipulate that.